Uses cross browser niceScroll to do scrolling on sidebar.

Fixes: #13544 

Firefox does not support `-webkit-scrollbar` and there is no alternative for FF. So for example Gmail falls back to no fancy scrollbar. Stuck with jQuery, which is a good solution, since we already use it. 

This also leaves the default scrollbar as is. 

![Screen_Shot_2016-02-18_at_11.02.26_AM](/uploads/1184f06b71a8d9097ef1e3450a0c0ab3/Screen_Shot_2016-02-18_at_11.02.26_AM.png)

Also fixes horz scroll issue: 

![Screen_Shot_2016-02-18_at_11.09.56_AM](/uploads/63e9a8e824cac69a2745dd4dd84d1dfb/Screen_Shot_2016-02-18_at_11.09.56_AM.png)

cc @creamzy @dzaporozhets 

See merge request !2873

Fix CI builds scheduler when first build in stage is allowed to fail

This fixes an edge case in CI builds scheduler when first build in stage was marked as allowed to fail.

Closes #3192

See merge request !2869

Fix labels for git clone/git fetch Project CI setting



See merge request !2842

Add example of creating build artifacts only for release tags.



See merge request !2649

Before this fix when there was only one relevant, previous build and it
failed, but was allowed to fail, entire build had been marked as
skipped.

Closes #3192

Re-add section about NGINX config and init script updates in 8.4->8.5 update doc

These sections were removed by !2766 but:
- even if the NGINX config wasn't modified, it might
  be in future updates so it's better to always have
  it instead of having to remember to add it depending
  on the changes
- the init script update section must be there since
  it's a safe command line that should be run on every update

This fixes https://github.com/gitlabhq/gitlabhq/issues/10031.

/cc @rspeicher @yorickpeterse 

See merge request !2815

Reduce code complexity on GitPushService#execute

Code complexity for gitlab-ce after this has been refactored:
```
  27.3: GitPushService#execute
```
This still needs to be merged into `gitlab-ee` presumably with conflicts... Perhaps we should create another issue for doing that?

I left the code sort of similar to what it was... If I could, I would have refactored most of the code into separate classes, etc. as it breaks probably all SOLID principles.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/13327


See merge request !2784

Bump unicorn to `~> 4.9.0`

Closes #2820 

See merge request !2843

Reopened MRs should also be considered as open.

Fixes #13539 

See merge request !2866

Remove remaining sqlite method call

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/13535

See merge request !2862

Add ability to see and sort on vote count from Issues and MR lists

Fixes #3763

* Sort options

![Sort Options](/uploads/df6543d574d4df8bf7e4496a876e2930/sort.png)

* Most popular

![Most popular](/uploads/bb92cc2fbef7b6b806dcdf8c52778fdd/most-popular.png)

* Least popular

![Least popular](/uploads/7988ed451922c81dc228419b5edbd7cd/least-popular.png)

See merge request !2781

Refactor 'git archive' hand-off to gitlab-workhorse

We have a nicer way now to hand off HTTP responses to gitlab-workhorse.

Companion MR: https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/36

See merge request !2675

Correct icon for milestones.



See merge request !2856

Sort line notes used in parallel diff by created_at


Fixes #13464.

See merge request !2858

Redirect /import to project page if no importing at all and repo exists


Fixes gitlab-org/gitlab-ce#13367.

See merge request !2857

Fixes #13464.

Handle nil commits in Gitlab::PushDataBuilder.build

Closes #13469

See merge request !2825

Expire caches after forking/importing a repository

cc @dblessing @DouweM 

Related issue: gitlab-org/gitlab-ce#13505

See merge request !2838

Fixes for showing images

- Render scrubbed SVG's inline, not via /raw/
- Use /raw/ requests on image diffs

Both of these are needed because of no longer eager loading blobs.

This a follow-up to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2830

Also see https://gitlab.com/gitlab-org/gitlab-ce/issues/13350

See merge request !2837

Fixes #13367.

Fix a bug preventing from doing subsequent edits in any Issuable sidebar

Fixes #13517. Fixes #12572.

### Issue

![impossible-subsequent-issue-edits-in-sidebar](/uploads/bd45c0effb46848641932d9cd38d3fe2/impossible-subsequent-issue-edits-in-sidebar.gif)

---

### Merge request

![impossible-subsequent-mr-edits-in-sidebar](/uploads/b4e1e3e93df4ac0a3d962df8b6139de9/impossible-subsequent-mr-edits-in-sidebar.gif)

/cc @jschatz1 @sytses 

See merge request !2848

Fix 500 error when comparing by tags

_Originally opened at !2787 by @klowner._

- - -

Fixes #13171.
Fixes #13370.

See merge request !2849

Fix double scrollbar issues

Sidebar double scrollbar issue fix.

![Screen_Shot_2016-02-16_at_9.22.49_PM](/uploads/cb950eda08ed5d3b4a6c6979c977e029/Screen_Shot_2016-02-16_at_9.22.49_PM.png)

See merge request !2851