Audit feature / permission changes in log

Audit events for membership changes of the group and project.

See merge request !250

Fix Enterprise Project Settings Icons

Font awesome was upgraded in CE and the corresponding enterprise project settings icons 'Groups' and 'Git Hooks' were not displaying any icon. The groups icon is exactly as it was pre-7.5. The git hooks icon is much different in the new font-awesome and did not make sense anymore. They do have a generic 'git' icon which I have included here and think looks nice.

## Pre-7.5:
![Screen Shot 2014-11-21 at 5.14.07 PM](https://gitlab.com/uploads/subscribers/gitlab-ee/12c3034fef/Screen_Shot_2014-11-21_at_5.14.07_PM.png)

## 7.5:
![Screen Shot 2014-11-21 at 5.14.24 PM](https://gitlab.com/uploads/subscribers/gitlab-ee/4f97728c19/Screen_Shot_2014-11-21_at_5.14.24_PM.png)

## After this merge request:
![Screen Shot 2014-11-21 at 5.14.17 PM](https://gitlab.com/uploads/subscribers/gitlab-ee/09b06bfddc/Screen_Shot_2014-11-21_at_5.14.17_PM.png)

See merge request !24

New packages links for 7.5

Added packages for the latest GitLab Version 7.5.1

See merge request !249

Add 7.4.5-ee packages

See merge request !248

Fix typo in documentation

Fixed a typo in a link to a configuration sample that was pointing to a non-existing page.

See merge request !245

Updated documentation for 7.5 release

Documentation for 7.5 release has been updated. Changes include:

- Pointed Ruby version in guides to 2.1.5
- Pointed gitlab-shell version in guides to 2.2.0
- Links to configuration samples for EE files point to the Subscribers' EE repo

See merge request !244

Renamed main update file to ...7.5.md, updated links and versions (Ruby to 2.1.5 and gitlab-shell to 2.2.0).

 Corrected ruby download link.

Improved git hook description

https://dev.gitlab.org/gitlab/gitlabhq/issues/1741

See merge request !243

Update changelog

See merge request !1258

Run 'GC.start' after every EmailsOnPushWorker job

This change removed a lot of large peaks of the Sidekiq memory growth graph on gitlab.com.

See merge request !1257

Update gitlab_git to 7.0.0.rc11

See merge request !1256

Gitlab.com uses special packages, build them first

See merge request !1255

Author attributes clean

See merge request !1254

Strip tags from branch name

See merge request !1251