Fix and test leave project display

The 'Leave this project' display on project page was broken. It was calling the method incorrectly, which returned `nil` and displayed nothing. 

This fixes the display and also adds 2 different tests for it.

cc/ @jvanbaarsen @stanhu Please review and merge if you think it looks good. Thank you!

See merge request !2166

New group page

Implementing from https://gitlab.com/gitlab-org/gitlab-ce/issues/3480#note_2722988

cc @skyruler 

For https://gitlab.com/gitlab-org/gitlab-ce/issues/3480

See merge request !2174

Hotfix for sidekiq-cron being loaded from Settingslogic with defaults

This fixes a regression with "Stack level too deep" from master.

See merge request !2173

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

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

New colour scheme

old
![Screenshot_2015-12-17_14.14.53](/uploads/5d6ac28b6d99186485d727a72cc8a662/Screenshot_2015-12-17_14.14.53.png)

new
![Screenshot_2015-12-17_14.15.07](/uploads/06e07fa3716aa8664b1507b390270285/Screenshot_2015-12-17_14.15.07.png)

* Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/2577

See merge request !2151

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

Sidekiq-cron configuration moved to gitlab.yml

When `sidekiq-cron` was introduced, jobs configuration where placed
in `schedule.yml` file.

As discussed in #3928, this is not desirable. 
We moved it to `gitlab.yml`, exposing only the "cron" part of the configuration.

See merge request !2087

Fix MR 500 when viewing the MR page

Fixes #2712 

See merge request !2167

Explicitly require Nokogiri 1.6.7.1 due to security issue

```
Name: nokogiri
Version: 1.6.7
Advisory: CVE-2015-5312
Criticality: High
URL: https://groups.google.com/forum/#!topic/ruby-security-ann/aSbgDiwb24s
Title: Nokogiri gem contains several vulnerabilities in libxml2
Solution: upgrade to >= 1.6.7.1
```

See merge request !2154

Also, make it not fail.

This is required since we parse URI later and remove the credentials

Also adds a spec for MergeRequestHelper to avoid having a regression
later on.

[ci skip]

Fixed wrong URL to "up for grabs" issue filter

[ci skip]

See merge request !2162

Allow admin to create new user identities

Fixes #2442 

See merge request !2077

Fix issue related cross-project MRs

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/4188

See merge request !2163

Allow account unlock via email

We see a lot of users get confused about what it means when your account gets
locked. Many try to reset their password and are still faced with a lockout.
With this change, users receive an email that allows them to unlock their
account immediately. The previous behavior where the account is auto-unlocked
after a time also still works.

See merge request !2049

Show git version on admin page

Before
![git-version-beore](/uploads/57444ad42220c9dfe8f187b8e399227f/git-version-beore.png)

After
![git-version-after](/uploads/cc1b52ae1a251c2c46d9626c040726ab/git-version-after.png)

gitlab-org/gitlab-ce#4077




See merge request !2101

Fix build coverage regex matching to allow captures.

Fixes #2644 

/cc @DouweM 

See merge request !2138

Backport JIRA service

Fixes #3839 

Move EE JIRA functionality back to CE.

- [x] Make it function in manual testing
- [x] Migrate JIRA-specific tests
- [x] Tests pass
- [x] Migrate documentation
- [x] Rollback to previous CE JIRA integration locally, activate on a project then try to migrate db and see if integration still works.
- [x] Final EE search for JIRA references

See merge request !2146

Added a spec for regex captures as well.

Fixes #2644

Remove CI_BUILD_BEFORE_SHA from CI documentation

As pointed in #3210, the environment variable isn't usable any more.

See merge request !2118

Clarify Windows shell executor artifact upload support

@ayufan noted that the runner does not support artifact upload for Windows shell executor. This adds a note so users aren't confused.

See merge request !2142

Don't create CI status for refs that doesn't have .gitlab-ci.yml, even if the builds are enabled

Fixes #3827 
Fixes #4157

/cc @grzesiek @dblessing 

See merge request !2139

Do not display project group/name when issue and MR are in same project

I noticed that things seem a bit cluttered for related merge requests
when displaying the group/project name for every item, even when it's
in the same project.

For merge requests that are in the same project as the issue we probably
don't need to display the 'in group / name' bit.

See merge request !2141