GL dropdowns in issuable form

## What does this MR do?

Changed all the issuable dropdown menus over to user GL dropdowns. This brings the dropdowns to be inline with the issuable filter dropdowns and allows for labels to be created whilst creating/editing an issuable.

## What are the relevant issue numbers?

Closes #12574 

## Screenshots (if relevant)


See merge request !4970

Projects blank state

## What does this MR do?

Adds a designed blank state to dashboard/projects

## What are the relevant issue numbers?

Part of #18519 

## Screenshots (if relevant)

![Screen_Shot_2016-06-24_at_17.14.46](/uploads/593ea1c5efa2310a0f94b2d56d94cf3c/Screen_Shot_2016-06-24_at_17.14.46.png)

See merge request !4909

Updated compare dropdowns

## What does this MR do?

Removes jQuery autocomplete from compare fields and replaces with GitLabs dropdowns.

## What are the relevant issue numbers?

Closes #18891 

## Screenshots (if relevant)

![Screen_Shot_2016-06-24_at_14.24.34](/uploads/f34370390183429f604fc48645390f2f/Screen_Shot_2016-06-24_at_14.24.34.png)

See merge request !4895

Pipeline row improvements

## What does this MR do?
Makes minor pipeline row improvements:
* Add margin between labels
* Remove underline hover style on status button
* Add margin between buttons if both retry and cancel are present

## What are the relevant issue numbers?
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/18920

## Screenshots (if relevant)
![Screen_Shot_2016-07-14_at_12.31.54_PM](/uploads/ae88651cb240ea90a0be58ab0ed65805/Screen_Shot_2016-07-14_at_12.31.54_PM.png)

See merge request !5258

Fix import_data being saved as a result of an invalid import_url

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19479

Seem that in all cases the `import_url` was an empty string. The `import_url` is now validated correctly and no longer creates the `import_data`even if it fails validation. <= Should cover cases 1, 3, and 4 of https://gitlab.com/gitlab-org/gitlab-ce/issues/19479#note_13005276

Also, it now rescues from all exceptions when importing from a URL, so we make sure the `import_status` is failed after that. Covers case 2 of https://gitlab.com/gitlab-org/gitlab-ce/issues/19479#note_13005276

See merge request !5206

Cleanup feature proposal template

## What does this MR do?

Changes the recommended template for feature proposals.

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

## Why was this MR needed?

I've been using the template for a while, and find that putting so many words into the h2 makes me think there's actual content there, until I realize I'm just reading the template text (again). I think we can get away with just putting `Description` as the header, and putting the suggested content for that section as plain text below for someone to replace.

## What are the relevant issue numbers?

## Screenshots (if relevant)

![image](/uploads/20a99c98a12aad84c1a7ec020f365b2f/image.png)

/cc @JobV 

See merge request !5240

Use default cursor for table header of project files

## What does this MR do?

Use default cursor for table header of project files.

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

Nope.

## Why was this MR needed?

The table header had a pointer cursor even though it was not clickable.

## What are the relevant issue numbers?

fixes #19612


See merge request !5165

Added shortcut to focus filters

## What does this MR do?

Adds shortcut `f` to focus filter inputs.

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

Is this a valid implementation?

Please check [this comment below](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4570#note_12359978)!

## Why was this MR needed?

Keyboard ninja UX ⚔ 

## What are the relevant issue numbers?

Closes #18120.

## Screenshots (if relevant)

![Screen_Shot_2016-06-09_at_18.34.56](/uploads/d4cfb6ec340c118f5227be3f16ffbed1/Screen_Shot_2016-06-09_at_18.34.56.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 !4763

Aria labels on top header links

## What does this MR do?

Added `aria-label` to the links in top header bar for accessibility.

## What are the relevant issue numbers?

Closes #12797 


See merge request !5205

Added author username tooltip in issuable header

## What does this MR do?

Adds the authors username as a tooltip to the header of issuables

## What are the relevant issue numbers?

Closes #13771 

## Screenshots (if relevant)

![Screen_Shot_2016-07-12_at_16.00.34](/uploads/9485150f1c9d4006384f18d08a07430f/Screen_Shot_2016-07-12_at_16.00.34.png)

See merge request !5209

Improves left static sidebar behaviour

List of changes:

* removed bottom 50px space that is no longer necessary with pin button at the top
* increased side padding so sidebar links are closer to counters
* use fixed weight pin icon so it correctly aligned with counters


cc @annabeldunstone @jschatz1 

See merge request !5251

Fix duplicated entry in changelog [ci skip]

## What does this MR do?

Removes duplicate changelog entries.

## What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/19822



See merge request !5252

List of changes:

* removed bottom 50px space that is no longer necessary with pin button at the top
* increased side padding so sidebar links are closer to counters
* use fixed weight pin icon so it correctly aligned with counters
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Add a UI guide note about number_with_delimiter



See merge request !5220

Include default callback URL (OAuth)

## What does this MR do?
Adds information on the OAuth callback URL

## Are there points in the code the reviewer needs to double check?
None

## Why was this MR needed?
This information was missing.

## What are the relevant issue numbers?
http://www.twitter.com/designingcode/status/753511397124866049

## Does this MR meet the acceptance criteria?

- [X ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)

See merge request !5246

Fix markdown rendering for label references

Fixes #14424, #19753, #19760

See merge request !5224

Upgrade Rails from 4.2.6 to 4.2.7.

Primarily just bug fixes.

See merge request !5236

This reverts commit 9ca633eb, reversing
changes made to fb229bbf.

Primarily just bug fixes.

Changelog: https://github.com/rails/rails/compare/v4.2.6...v4.2.7

Actually render old and new sections of parallel diff next to each other

See merge request !5173

Dropdown loading time preformance fix

## What does this MR do?
Optimizes the performance of the dropdown load time by just sending the required data to load the dropdown instead of the full object

This MR aims to fix #17474 

See merge request !5113

Keeps issue number when importing from Gitlab.com

## What does this MR do?

Keeps issue number when importing from `Gitlab.com`

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

No.

## Why was this MR needed?

With these changes we doesn't loose the issue references when importing from `GitLab.com`.

## What are the relevant issue numbers?

Closes #15235 

/cc @cpm @jweerdt

See merge request !5193