Allow subsequent validations in CI Linter

Closes #5851

See merge request !2368

Improve performance of getting issues on group level

For testing I used the URL http://localhost:3000/groups/gitlab-org/issues?milestone_title=8.1. Prior to these changes said URL would take about 10-12 seconds to load. By applying these changes the loading time has been reduced to roughly 2-3 seconds. 

There's still some stuff going on in some views that I have to look at, resolving those changes might reduce the loading time a bit more. I also still have to check if I didn't break too many tests.

Fixes: gitlab-org/gitlab-ce#3707 gitlab-org/gitlab-ce#4071 

See merge request !2318

Closes #5851

These specs assumed data was still sorted by timestamp, instead of by
ID.

Adds settings menu to the top for editting and leaving projects

@creamzy @skyruler @dzaporozhets 
Menu contents depends on user's rights.

Fixes #4221


![Screen_Shot_2015-12-23_at_10.02.47_PM](/uploads/daeaef937bf9d9f4db7ccb674e344ac1/Screen_Shot_2015-12-23_at_10.02.47_PM.png)
![Screen_Shot_2015-12-23_at_10.02.41_PM](/uploads/58eb4eea7d640f01d7f05c2a408a2c04/Screen_Shot_2015-12-23_at_10.02.41_PM.png)
![Screen_Shot_2015-12-23_at_10.02.55_PM](/uploads/4b2ae027a13efcbad3eb81b04f134c4f/Screen_Shot_2015-12-23_at_10.02.55_PM.png)
![Screen_Shot_2015-12-23_at_10.04.47_PM](/uploads/bd5d9d8ddd72d16d74c32c6c1f569776/Screen_Shot_2015-12-23_at_10.04.47_PM.png)


See merge request !2195