Fixes an issue where values couldnlt be unselected

New dropdown UI

See #3279 for the designs

See merge request !3110

Fix projects pagination via ajax

Basically was not implemented. Finishes our projects list refactoring. 
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !3155

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

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

See #3279 for the designs

Added specs for Issue#referenced_merge_requests

Added these while looking into https://gitlab.com/gitlab-org/gitlab-ce/issues/13651.

See merge request !3125

Add shortcut to toggle markdown preview

Allow to toggle markdown preview with shortcut `ctrl+shift+p` (`cmd+shift+p` on OSX).

- If the user is focused on a md textarea, `ctrl-shift-p` will show the preview, otherwise native browser event is fired
- The textarea is re-focused after disabling the preview tab
- Results of markdown render is cached for fast toggles

I'm on linux, so if someone can test it on OS X, it would be great!

Closes #14038

See merge request !3111

Retry bundler and apt-get



See merge request !3146

Fixed the GitPushService specs

See merge request !3139

Add a `gemojione:sprite` Rake task

This task will generate a standard and Retina sprite of all of the
current Gemojione Emojis, with the accompanying SCSS map.

It will not appear in `rake -T` output, and the dependent gems are not
included in the Gemfile by default, because this task will only be
needed occasionally.

See merge request !3130

Fix error 500 in Todos

Closes #14095 

Closes #14075 

Closes #14109

Closes #14151

See merge request !3141

This task will generate a standard and Retina sprite of all of the
current Gemojione Emojis, with the accompanying SCSS map.

It will not appear in `rake -T` output, and the dependent gems are not
included in the Gemfile by default, because this task will only be
needed occasionally.

[ci skip]