Improve email threading

This is a follow-up to !112 : it improves email threading, without changing the receiver of the emails.

* Subject of answers to an existing thread begins with `Re: ` (required by Mail.app)
* Send a 'In-Reply-To' header along the 'References' header

Sanitize rake check output

Fixes #1206

See merge request !952

Cleaner help page

Focus on documentation. Move quick help section to right. Remove unnecessary styling

See merge request !950

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

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

Notification when reopened issue or mr

Fixes #1396

See merge request !939

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

Show full commit message and author name for Email on push service

Fixed #1305

![Screenshot 2014-07-04 17.42.47](https://dev.gitlab.org/uploads/dzaporozhets/gitlabhq/55696faea6/Screenshot_2014-07-04_17.42.47.png)

See merge request !949

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

Adds rake task to clean up deleted LDAP users

Call every service, even if one fails

Flash message after signup

Fixes #1366

See merge request !948

Improve ci widget ui

See merge request !943

Don't show remove branch checkbox for MR from fork

Fixes #1359

See merge request !942

Group milestones improvements

Fixes #1400

Fixes #1401

Fixes #1402

See merge request !946

Correct active link for group milestones

Fixes #1399

See merge request !945

Fix for public access doc

See merge request !947

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

Remove source button checkbox always try to remove branch in target
project. For fork source & target projects are differents - so we hide
checkbox from UI. After MR accepted you can easily remove branch with
'Remove branch' button that do remove branch call to valid project
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixed labels for closed issues/mr in search results

See merge request !941

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

* send a 'In-Reply-To' header along the 'References' header
* subject of answers to an existing thread begins with 'Re: '

No notification for merger

Fixes #1378

See merge request !935

No notification for project creator

Fixes #1378

See merge request !937

No need for creating satellites

Satellites are created automatically now.

See merge request !905

Use the correct clone link for the DB converter

See merge request !938