This also refactores ProjectSelect adding some decorator-like functions.

Discussed it here:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2831#note_4190228

This also wrapps entire process into transation, as rewriting references
may have large memory footprint.

Fix wiki search results point to raw source

Closes https://github.com/gitlabhq/gitlabhq/issues/9581

See merge request !3138

Follow the CSS Style Guide rules for unitless zero values.

Discussed in #14299.

cc: @rspeicher @jschatz1 

See merge request !3259

Updated Emoji Rake task to conform to style guide.

Discussed in #14299.

[ci skip]

omniauth-auth0 gem support

See merge request !3246

Fixes issue with dropdown caret being incorrect color

Previously:

![Screen_Shot_2016-03-16_at_19.31.20](/uploads/b887a7b8249f172513c68289c52a4cf7/Screen_Shot_2016-03-16_at_19.31.20.png)

Now:

![Screen_Shot_2016-03-16_at_19.29.37](/uploads/9c0d6a3002c18a8c7890df8dce612dcb/Screen_Shot_2016-03-16_at_19.29.37.png)



See merge request !3254

See merge request !3249

Follow the CSS Style Guide rules for HEX colors.

Use lowercase letters and shorthand values for HEX colors where possible, in accordance with the CSS Style Guide.

Discussed in #14299.

\cc @jschatz1 @rspeicher

See merge request !3238

Install Git 2.7.3, not 2.4.3



See merge request !3248

On PostgreSQL the index is created concurrently.

Fixes gitlab-org/gitlab-ce#14325