Merge when build succeeds

### What does this MR do?
Adds a button to a MR when the build/ci is running so it can be merged when/if the build is successfull.

### Are there points in the code the reviewer needs to double check?
English spelling and whether or not the grammer is correct.

### Why was this MR needed?
When you expect its all good, and don't want to revisit the current MR it can be accepted allready.

### What are the relevant issue numbers / Feature requests?
Fixes #2640 -- although `Merge if green` is replaced with `Merge when the build succeeds` the general idea is the same.

### Screenshots (if relevant)
![Screenshot_from_2015-12-07_10-34-39](/uploads/b90b558b6ad6c8266bc9c96120d86f96/Screenshot_from_2015-12-07_10-34-39.png)

![Screenshot_from_2015-11-02_17-26-56](/uploads/9f52f56e3c5e9ec63cb8f42978c92a52/Screenshot_from_2015-11-02_17-26-56.png)
![Screenshot_from_2015-11-02_17-27-03](/uploads/119fc18c9b15ff73dc38010ac5b6244a/Screenshot_from_2015-11-02_17-27-03.png)

![Screenshot_from_2015-12-03_10-08-14](/uploads/bad7b35c7d129981d43631877c958be0/Screenshot_from_2015-12-03_10-08-14.png)

![Screenshot_from_2015-11-02_17-27-16](/uploads/b616d750a16cc11ba72f2ca84213515e/Screenshot_from_2015-11-02_17-27-16.png)

### Further considerations
What if there are minor things needed solving, e.g. Rubocop, the current implementation will reset the approved status of the MR. It might be a consideration keep the approval for team member, or even guests. This would require an extra option in the Admin screen, though might add extra value.

#### TODO
- [x] Docs
- [x] Specs

/cc @DouweM @rspeicher

See merge request !1729

Introduce CI documentation for services and languages

This introduces guide for PHP, a bunch of services (databases) and cleans up some docker references.

With this there are bunch of example projects in https://gitlab.com/groups/gitlab-examples.

/cc @JobV @axil 

See merge request !1917

# Conflicts:
#	app/controllers/projects/merge_requests_controller.rb
#	config/routes.rb

Update annotations



See merge request !2033

Fix only 20 group members showing on project member page
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !2030

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

Add Builds tab to MR detail page

## Before

![Screen_Shot_2015-12-08_at_13.21.04](/uploads/0d26060bef78f3de076e33439b8a4789/Screen_Shot_2015-12-08_at_13.21.04.png)

## After

![Screen_Shot_2015-12-08_at_13.25.20](/uploads/be7d7fd6d4fc8c5cc366b5b3778b813a/Screen_Shot_2015-12-08_at_13.25.20.png)

Fixes #3907

See merge request !2016

Default target branch to patch-n when editing file in protected branch

Fixes #3441

See merge request !2021

Update documentation about automatic issue closing

RE !1933

See merge request !2000

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1917#note_2833978

# Conflicts:
#	app/views/projects/merge_requests/widget/_heading.html.haml
#	app/views/projects/merge_requests/widget/open/_accept.html.haml

# Conflicts:
#	app/controllers/projects/merge_requests_controller.rb
#	app/views/projects/merge_requests/widget/_heading.html.haml

Make cross-project reference's clipboard target less naive

See !2023

See merge request !2024

See !2023

Make tab target selectors less naive

Prior, any of the specified IDs could have been hijacked by a table of
contents header, breaking the tab functionality. For example, a `##
Notes` header would get the id `notes` and prevent the Discussion tab
from being activated.

Closes #3908

See merge request !2023

Prior, any of the specified IDs could have been hijacked by a table of
contents header, breaking the tab functionality. For example, a `##
Notes` header would get the id `notes` and prevent the Discussion tab
from being activated.

Closes #3908

Block LDAP user when they are no longer found in the LDAP server

Currently, if a user is deleted from LDAP the `Gitlab::Ldap::Access.allowed?` method will return `false`, but the user will not be blocked. This means that the user would be able to continue using GitLab if they are already logged in, or when performing Git over SSH operations.

After this change, users will be blocked when they no longer exist in LDAP. There is still a one hour LDAP check cache time in effect, so the change is not immediate. This is noted in the documentation.

cc/ @DouweM @dzaporozhets 

See merge request !2022

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

Update project repository size and commit count during import:repos task

Closes #3848

See merge request !2011

Closes #3848