Hotfix for sidekiq-cron being loaded from Settingslogic with defaults on Gitlab EE

This is a followup on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2173

See merge request !91

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

Pages doc fixes

cc @DouweM 

See merge request !90

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>

* Pages are enabled by default on each project
* Add note about using the `only` parameter

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 specific changes for EE

Following the changes at gitlab-org/gitlab-ce!2087, we moved EE specific configurations from `schedule.yml` to `gitlab.yml`, following the discussion at gitlab-org/gitlab-ce#3928

See merge request !78

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

Use the example.com domain for consistency



See merge request !87

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]

[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

Use Jenkins GitLab Plugin

Fixes #106

Deprecate the existing Jenkins service, which uses GitLab Hook plugin.
Adds support for GitLab Plugin which utilizes the GitLab commit status
API. The overall experience is much better.

See merge request !79