Avoid allocations in Ability class.

Fix explore projects page UI

# Before

![Screenshot_2015-12-24_14.13.03](/uploads/fdae7648acc8b8076709e4bfc867a5f8/Screenshot_2015-12-24_14.13.03.png)


# After

![Screenshot_2015-12-24_14.11.29](/uploads/b1ecd3bebfadab9d2ceabaae27046271/Screenshot_2015-12-24_14.11.29.png)



cc @jschatz1 @skyruler 
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>


See merge request !2202

Fix NewBranchForm spec

cc @vsizov 

See merge request !2204

Dropdowns for clone. Star and Fork with new count areas. Star and Unstarred Works now

Fixes #2876 and #3482
Used existing styles. <br/>
Did not attempt to make pixel perfect as styles already exist. <br/>

![Screen_Shot_2015-12-18_at_5.24.56_PM](/uploads/a79ba1e0be0232f2aeef8a43f3253479/Screen_Shot_2015-12-18_at_5.24.56_PM.png)

See merge request !2156

Emoji picker search

depend on !2172

Issue https://gitlab.com/gitlab-org/gitlab-ce/issues/3576

!!! Should be merged after https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2198

![Screenshot_2015-12-23_11.44.57](/uploads/01da0b62c3c234307142e2c4db68e53f/Screenshot_2015-12-23_11.44.57.png)

See merge request !2186

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

Fix Error 500 when global milestones have slashes

* Closes #4226

* Closes https://github.com/gitlabhq/gitlabhq/issues/9921

See merge request !2182

nav full width

old
![Screen_Shot_2015-12-21_at_3.47.01_PM](/uploads/ef47c61eb33521087fc40d400d01cba8/Screen_Shot_2015-12-21_at_3.47.01_PM.png)

new
![Screenshot_2015-12-24_12.16.53](/uploads/30cf37886b3710a22daa0b82583975e9/Screenshot_2015-12-24_12.16.53.png)


See merge request !2200

Automatically fork a project when not allowed to edit a file.

Fixes #3215.

To do:

- [ ] Add tests

-----

## "Edit" button on file in a project the user does NOT have write access to

![edit_file](/uploads/7602157420768aef483a6586bba2d164/edit_file.png)

## Clicking will automatically create a fork

![during_fork](/uploads/32f4f5dff9f24ea99522000b0bf881c5/during_fork.png)

## When the fork has been created, the user is returned to the edit page on the original project with a notice

![edit_notice](/uploads/94ed1319404370ff1e9c0d672fb41e03/edit_notice.png)

## The user cannot change the target branch and is informed that editing will start an MR

![edit_footer](/uploads/4da68d4795c7177e575b7c434d16eeae/edit_footer.png)

## Hitting "Commit changes" will commit and start an MR from my fork to the origin project

![Screen_Shot_2015-12-17_at_23.38.08](/uploads/d777a4db6f38a5a1be84031694465bc1/Screen_Shot_2015-12-17_at_23.38.08.png)

-----

## "Create file, "Upload file" and "New directory" buttons in a project the user does NOT have write access to

![new_directory](/uploads/72f556248f30d6652523bbb4be01b3e0/new_directory.png)

## Clicking any of these options will automatically create a fork

![during_fork](/uploads/32f4f5dff9f24ea99522000b0bf881c5/during_fork.png)

## When the fork has been created, the user is returned to the tree page on the original project with a notice

![new_directory_notice](/uploads/a1a3e11308ae0e8f0913fae6813a37ed/new_directory_notice.png)

## Clicking "New directory" again will show the modal. The user cannot change the target branch and is informed that editing will start an MR

![new_dir](/uploads/99ca8cbfb2f70603e352b3fdf67b6281/new_dir.png)

## Hitting "Create directory" will commit and start an MR from my fork to the origin project

![Screen_Shot_2015-12-17_at_23.39.19](/uploads/3713d0235abf831361b803a6198c5bc1/Screen_Shot_2015-12-17_at_23.39.19.png)

cc @dzaporozhets @skyruler

See merge request !2145

Fix/visibility level setting in forked projects

Fixes #3136

/cc @DouweM 

See merge request !1744

Add JS validation for invalid characters  in branch name

Fixes #3293 

Demo:

![out-1080p](/uploads/ba21c359b6b8b440c40cacf772ec0df7/out-1080p.gif)


See merge request !2122

Fix redirect to wrong URL when merging and MR detail URL has an anchor.

Closes #4189

See merge request !2169

Emoji picker: better alias handling

related to https://gitlab.com/gitlab-org/gitlab-ce/issues/3576

See merge request !2198

Bump underscore-rails to ~> 1.8.0

Addresses #2857

See merge request !2193

fixes the search for projects

Also makes improvements for jQuery queries. <br/>
@creamzy @skyruler <br/>
Fixes issues introduced in MR for #3943

See merge request !2194

Fix spelling of "it's" to "its" where appropriate.

[ci skip]

See merge request !2196

Fix Error 500 when doing a search in dashboard before visiting any project

If a search turned up an issue, under certain conditions you would see this error:

```
ActionView::Template::Error (undefined method `path_with_namespace' for nil:NilClass):
     6:   - if issue.description.present?
     7:     .description.term
     8:       = preserve do
     9:         = search_md_sanitize(markdown(issue.description))
    10:   %span.light
    11:     #{issue.project.name_with_namespace}
    12:   - if issue.closed?
  lib/gitlab/markdown/upload_link_filter.rb:36:in `build_url'
  lib/gitlab/markdown/upload_link_filter.rb:31:in `process_link_attr'
  lib/gitlab/markdown/upload_link_filter.rb:18:in `block in call'
  lib/gitlab/markdown/upload_link_filter.rb:17:in `call'
  lib/gitlab/markdown.rb:127:in `gfm'
  lib/gitlab/markdown.rb:24:in `render'
  app/helpers/gitlab_markdown_helper.rb:61:in `markdown'
  app/views/search/results/_issue.html.haml:9:in `block in _app_views_search_results__issue_html_haml__4127460390996300432_59973760'
  app/views/search/results/_issue.html.haml:8:in `_app_views_search_results__issue_html_haml__4127460390996300432_59973760'
  app/views/search/_results.html.haml:20:in `_app_views_search__results_html_haml__589475855773452465_61761440'
  app/views/search/show.html.haml:5:in `_app_views_search_show_html_haml___1852335078065998536_69780120'
```

Confirmed this is issue still happens in GitLab 8.4, and it also happens on GitLab.com. Here's how to reproduce:

1. Login in a new browser.
2. Enter a search term on the top right that will land a hit in the "Issues" (e.g. GitLab).
3. Click on "Issues" tab. You should get an Error 500.

The issue is that @project isn't assigned to anything.

See merge request !2110

Make migrations reversible

See merge request !2191

Addresses #2857