Improve markdown

Based on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4975 (thanks @sheerun) with small changes on top

cc @iamphill @tauriedavis 

See merge request !5314

Revert "Revert "Merge branch '18193-developers-can-merge' into 'master'""

## What does this MR do?

Reverts the revert of !4892 which lacked an EE MR at the time. This has been done in gitlab-org/gitlab-ee!564.

## What are the relevant issue numbers?

Closes #19872.

See merge request !5310

Fix activity heatmap to show proper day name.

## What does this MR do?
This MR fixes issue #19909.

## Are there points in the code the reviewer needs to double check?
Not necessarily, it's pretty straightforward, buuuut

There was some discussion about whether GL wanted the activity heatmap to start on Monday or Sunday, this fix makes it start on Sunday, if GL is wanting it to start on Monday then some more substantial changes need to be made on the `calendar.js.coffee` script.

## Why was this MR needed?
The amount of day names that were off from their dates was too damn high! :P 

## What are the relevant issue numbers?
Directly #19909 

Also some related discussion (feature discussion):
#19282, #5988

## Screenshots (if relevant)
**Currently on GL.com**
![Screen_Shot_2016-07-16_at_10.56.02_PM](/uploads/b45cfc56c29a8865a2bdc1f798409706/Screen_Shot_2016-07-16_at_10.56.02_PM.png)

**After MR**
![Screen_Shot_2016-07-16_at_10.56.30_PM](/uploads/d8655bb259ced443a2c572ff03dcb8bb/Screen_Shot_2016-07-16_at_10.56.30_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5303

Don't blow up in tree view on empty repo

## What does this MR do?

Stop the empty repo page blowing up with a 500 error when a user's default view is tree view.

## Are there points in the code the reviewer needs to double check?

Don't think so.

## Why was this MR needed?

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4997 made sure that the `tree` filter was only called if the user's default project view is tree, but left out the empty repo check. When users visit an empty repo with the tree view as default, they now get a 500.

## What are the relevant issue numbers?

Closes #19928.

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~ (bug introduced in same release)
- ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~API support added~~
- Tests
  - ~~Added for this feature/bug~~
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5317

Don't parse Rinku returned value to DocFragment when didn't change original html string.

See merge request !5311

- This was introduced (at some point) while rebasing `master` against
  the "developers can merge" feature branch.

- https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5310#note_13139705

Disable transaction when adding index for Ci::Pipeline

## What does this MR do?
Adds missing `disable_ddl_transaction!`

## Why was this MR needed?
Fixes a broken migration for PostgreSQL


See merge request !5319

Store when and yaml variables in builds table

## What does this MR do?
Stores `when` and `yaml_variables` in `ci_builds` table.

## Why was this MR needed?
This is done in order to simplify the code responsible for creating a pipeline builds.

## What are the relevant issue numbers?
This made as a pre-step for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5295.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5296

Make docker registry work with location redirects when external storage is used

## What does this MR do?

Honor `Location:` header when working with local registry.
Location makes it possible to download manifests from external storage.

## What are the relevant issue numbers?

Fixed https://gitlab.com/gitlab-org/gitlab-ce/issues/18477

## Remark

Adding `FollowRedirects` makes that we leak `Authorization:` in followed requests.

That is why it is implemented manually and we are explicitly removing `Authorization` header.

cc @marin @twk3 

See merge request !4677

Add Pending Tab to Builds

## What does this MR do?

Add Pending Tab to Builds and separate "running" and "pending" jobs in UI.

## Why was this MR needed?

Increase visibility to "pending" .

## What are the relevant issue numbers?

Closes #19408 

## Screenshots

Before:
![Zrzut_ekranu_2016-07-05_o_11.52.48](/uploads/01dc1f3664f5aacb2ec09d52d19c521e/Zrzut_ekranu_2016-07-05_o_11.52.48.png)

After:
![Zrzut_ekranu_2016-07-05_o_11.51.34](/uploads/f3be02427996fecf50c65dd51ce1b9fb/Zrzut_ekranu_2016-07-05_o_11.51.34.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

cc @ubudzisz @yorickpeterse @grzesiek @tmaczukin @zj [@chastell](https://github.com/chastell) [@tomash](https://github.com/tomash)

See merge request !5084

Allow empty repos on import/export

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19849

See merge request !5312

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

API: Expose due_date for issues

## What does this MR do?

Add support for the `due_date` of issues to the API.

## What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/18696

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5212

Merge branch 'master' of gitlab.com:gitlab-org/gitlab-ce into store-variables-and-when-in-builds-table

# Conflicts:
#	db/schema.rb

Track a user who creates a Pipeline

## What does this MR do?
This adds additional column to pipelines to track user who is creating pipelines.

## Why was this MR needed?
This is to make it possible to show all pipelines created by specific user and to later solve: https://gitlab.com/gitlab-org/gitlab-ce/issues/18054

## What are the relevant issue numbers?
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18992

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5272

Fix creation of deployment on build that is retried, redeployed or rollback

## What does this MR do?
Add missing `environment` to be copied when retrying a build.

## Why was this MR needed?
The retried builds did not create a deployments.

## What are the relevant issue numbers?
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19521

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5275

Fix CHANGELOG

Fix build spec for pending tab

Add Pending Tab to Project Builds

Update CHANGELOG

Allow to access Container Registry for Public and Internal projects

## What does this MR do?
Adds missing ability `read_container_image` for `public scope` which affects users accessing public and internal projects.

## Why was this MR needed?
Previously, we allowed to use container registry for anonymous users, but did not allow to do the same for logged in.
This MR makes it possible.

## What are the relevant issue numbers?
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18176 https://gitlab.com/gitlab-org/gitlab-ce/issues/19668 https://gitlab.com/gitlab-org/gitlab-ce/issues/19117

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5279

Fix stage status shown for pipelines

## What does this MR do?
Properly calculates a status of stage when shown on a list of pipelines

## Why was this MR needed?
Previously we were calculating a status for all builds, including retried ones. 
This were affecting a overall stage status when a build were retried.

## What are the relevant issue numbers?
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18896 https://gitlab.com/gitlab-org/gitlab-ce/issues/18150

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5277

This reverts commit 530f5158.

See !4892.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Limit number of project export retries to 3

I think 3 should be a sufficient number of retries - at the moment we were doing 20+

This will only send a maximum of 3 emails if the project export went wrong. Tested - project import is not affected.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18966

See merge request !5267

Fix LFS CI fetch

## What does this MR do?
Fixes LFS fetching for CI objects that were kind of broken.

## Why was this MR needed?
This also refactors LFS tests to be a blackbox tests instead of whitebox tests. Actually testing GrackAuth instead of LFSRouter.

## Related isssues
Resolves: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1199

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5270

Allow a project import URL to be blank to prevent false positives in validation

Projects that happen to have blank import URLs were failing validation, causing project settings not to be saved. Loosen the requirement and don't try to use the import data if the URL isn't present.

Closes #19893

See merge request !5309

Fix not normalized emoji paths

## What does this MR do?
It normalizes emoji names in `api` and `toggle_award`

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?
User was able to store +1 and thumbsup to databse, causing UI inconsistency.

## What are the relevant issue numbers?
Fixes #19104 

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5060

preventing settings from being saved