Fix images in emails

Closes #18474. The confirmation email is actually the only one that uses the `image_tag` helper at the moment, but this will work for all of them:
```shell
$ ag image_tag -G mailer
app/views/layouts/devise_mailer.html.haml
13:              = image_tag('mailers/gitlab_header_logo.png', id: 'logo', alt: 'GitLab Wordmark')
24:                  = image_tag('mailers/gitlab_tanuki_2x.png', alt: 'GitLab Logo')
```

See merge request !4705

Lighten each logo path color instead of white

## What does this MR do?
Changes highlight/loading colors of tanuki from white to a lighter version of each path color

## Why was this MR needed?
Since the logo is no longer on the dark sidebar, the highlight color was getting lost against the light gray background

## What are the relevant issue numbers?
Closes #18521 

## Screenshots (if relevant)
![logo](/uploads/3743925862fa8e17d2fec426f7e4c853/logo.gif)

cc @jschatz1 @lbennett @dzaporozhets 

See merge request !4690

Banzai::Filter::ExternalLinkFilter use XPath

See merge request !4702

Use gitlab_git 10.1.4

Towards https://gitlab.com/gitlab-org/gitlab-ce/issues/18690,
following https://gitlab.com/gitlab-org/gitlab_git/merge_requests/87 .

See merge request !4706

Improve pipeline status in case that pipeline has no jobs

## What does this MR do?

This MR resolves problem with pipeline status when there are no build in pipeline.

This can happen when builds were skipped - for example - by using `only`/`except` keyword in `.gitlab-ci.yml`.

## What are the relevant issue numbers?

Closes #17977

See merge request !4403

Banzai::Filter::UploadLinkFilter use XPath

See merge request !4703

Fix permission checks in member row (backport from gitlab-org/gitlab-ee!460)

## What does this MR do?

It improves the check we use to display or not the members' access and controls in the members list.

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

No, I replaced an helper with just a permission check so I think it's a better solution.

## Why was this MR needed?

There were a spec failure in gitlab-org/gitlab-ee!460 because of the refactor done in the "request access" MR.

## What are the relevant issue numbers?

None.

## Does this MR meet the acceptance criteria?

- No CHANGELOG needed
- [x] 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 !4670

Turn Group#owners into a has_many association

## What does this MR do?

This turns the regular method `Group#owners` into a `has_many` association.

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

As far as I can tell there's no way to do this without using an intermediate association, but perhaps I'm missing something. The reason an intermediate association is needed is because the supplied Proc is applied to the _final_ association (the one returning users), this means that when using a single `has_many` you can't filter out any intermediate rows (e.g. group members).

## Why was this MR needed?

This code being a regular method would prevent eager loading of the owners of a Group, turning it into a `has_many` association resolves this problem. This was discovered in !4410.

## What are the relevant issue numbers?

None.

## 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
  - [ ] All builds are passing
- [x] 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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !4676

Make project_id nullable

## What does this MR do?
Fixes the broken migration which is not in sync with `db/schema.rb`.

It's to solve https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/469.


See merge request !4701

This allows the owners to be eager loaded where needed.

Update migration_style_guide.md with new details

See merge request !4693

Hide the Todo button in the collapsed issuable sidebar.

## What does this MR do?

Fixes a bug where the "Add Todo" button was displayed in the collapsed sidebar.

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

This shouldn't remove any other elements from the collapsed sidebar.

## What are the relevant issue numbers?

None

## Screenshots (if relevant)

Before:

![Screen_Shot_2016-06-15_at_11.41.46_AM](/uploads/27a1ace58cf8c44ad96accd3d0b32f11/Screen_Shot_2016-06-15_at_11.41.46_AM.png)

After:

![Screen_Shot_2016-06-15_at_11.40.53_AM](/uploads/91a8585680fc482682d0efafdba4d599/Screen_Shot_2016-06-15_at_11.40.53_AM.png)

See merge request !4686

Fix long commit message scroll issue.

Fixes horizontal scrollbar for long commit description.

## Before
![before_](/uploads/d261e26044d8ab451bc7768b16316253/before_.png)

## After
![after](/uploads/f27227a77d25d80b797e3ffc916d1957/after.png)

See merge request !4643

Show categorised search queries in the search autocomplete

Fixes #5885 

It works in 3 categories, Dashboard, Groups and Project.

## Dashboard context
![for-dashboard](/uploads/3a59f6ec008a972495597c8f2691c385/for-dashboard.png)

## Group context
![for-group](/uploads/f7aa413d56330a1d9b2e5562f95badf7/for-group.png)

## Project context
![for-project](/uploads/dabe04cf8758a056cf7b03da001ffd91/for-project.png)


## Screencast
![category-search-dropdown](/uploads/4d9513dcd6ccb6e24adefdf65f9bc778/category-search-dropdown.gif)



See merge request !4499

# Conflicts:
#	app/assets/javascripts/lib/common_utils.js.coffee

Toggle whitespace button for compare page

## What does this MR do?

Adds whitespace button to compare branches page.

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

Ruby code.

## Why was this MR needed?

Compare branches UX

## What are the relevant issue numbers?

Closes #17881.

## Screenshots (if relevant)

![Screen_Shot_2016-06-09_at_18.39.48](/uploads/8995a7bc8bea7fa3ff19446ebe49fb88/Screen_Shot_2016-06-09_at_18.39.48.png)

## 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)
- [ ] 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 !4569

Fix emoji block selector.

Fixes #18465 and #18577

See merge request !4604

Update CHANGELOG

[ci skip]

See merge request !4695

Revert "Merge branch '18047-event-item-links-dont-look-like-links' into 'master'"

## What does this MR do?

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

## Why was this MR needed?

## What are the relevant issue numbers?

## Screenshots (if relevant)

## 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 !4692

[ci skip]

[skip]

[ci skip]

[ci skip]

[ci skip]

[ci skip]

This reverts merge request !4544

Replace raphael-rails with raphael.js and split it from the rest of the JS

## What does this MR do?

Removes raphael.js and its related libraries from the default JS bundle.

It also removes raphael-rails because the gem is unmaintained and – for whatever reason – didn't want to cooperate with the way I was trying to require it.

This brings the default (compressed and minified) application.js from 354KB after the d3 MR (!4394) down to 324KB.

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

That tests pass and that there aren't errors on any pages (especially the Network page).

## Why was this MR needed?

It's only used on the Network page and was using way too much bandwidth for just one page.

## What are the relevant issue numbers?

#14372 #13165 

Follow-up to !4394 and !4516.

cc: @jschatz1 

See merge request !4519

Updated '.event-item a' color

## What does this MR do?

Changes the color of `.event-item` links.

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

Did you want this restricted only to the activity page or anywhere showing `.event-item`'s?

## Why was this MR needed?

UX

## What are the relevant issue numbers?

Closes #18047.

## Screenshots (if relevant)

![Screen_Shot_2016-06-08_at_20.07.54](/uploads/9670fbeb6fac7a334a83e11ffc05148c/Screen_Shot_2016-06-08_at_20.07.54.png)

See merge request !4544

added hover state to top nav links

## What does this MR do?

Adds hover state to top nav links.

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

Ney.

## Why was this MR needed?

UX.

## What are the relevant issue numbers?

Closes #18301.

## Screenshots (if relevant)

![Screen_Shot_2016-06-07_at_23.23.45](/uploads/dac8ed99eca99fbcccbd98028e947ee1/Screen_Shot_2016-06-07_at_23.23.45.png)

See merge request !4521

Due date can be removed from milestones

## What does this MR do?

Adds a button to milestone form to allow user to remove due date 

## What are the relevant issue numbers?

Closes #15063 

## Screenshots (if relevant)

![Screen_Shot_2016-06-02_at_08.32.03](/uploads/8bd4446abde745dd5b1e140a887ec694/Screen_Shot_2016-06-02_at_08.32.03.png)

See merge request !4428