Fix Error 500 when comparing non-existing branches

Closes #2593

See merge request !1355

Remove deleted milestones from merge requests

This is related to !1348 but thought it would be useful as a separate MR. This MR removes deleted milestone IDs from any merge request.

Closes https://github.com/gitlabhq/gitlabhq/issues/9643

See merge request !1350

Allow relative links to go up one directory level

See merge request !1352

Closes https://github.com/gitlabhq/gitlabhq/issues/9643

Rename reply_by_email to incoming_email to prepare for the future.

Closes #2579.

See merge request !1367

CI import improvements



See merge request !1369

Fixed MR handling when GitLab CI project is not present

This is copy of !1371

/cc @jacobvosmaer @vsizov @dzaporozhets



See merge request !1373

More tweaks to make note edit/preview CSS consistent

Closes #2585

See merge request !1378

Fetch merge request ref if it is missing when visit MR page

This will fix merge problem for merge requests between forks created
before 8.0
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Needed for 8.0

Fixes #2580 

See merge request !1377

Closes #2585

Remove milestones from merge requests when milestones are deleted

Destroying a milestone does not remove it from existing merge requests. This MR fixes that.

Requires f4816372 to pull in as well.

Reported by https://github.com/gitlabhq/gitlabhq/issues/9643

See merge request !1348

Link project repo size to files



See merge request !1374

Remove CI button from project home panel

Since we already have a "Continuous Integration" item in the sidebar now, I don't think we need "CI" on the project page.


See merge request !1372

Use fixed-width icons in CI nav sidebar.



See merge request !1376

Use consistent styling for number of commits in CI nav sidebar

Before:

![Screen_Shot_2015-09-21_at_15.00.28](https://gitlab.com/gitlab-org/gitlab-ce/uploads/9005f606842936d415a3b67890b8af88/Screen_Shot_2015-09-21_at_15.00.28.png)


After:

![Screen_Shot_2015-09-21_at_15.00.43](https://gitlab.com/gitlab-org/gitlab-ce/uploads/08c897b65f82fab5f2c386a0d21c64af/Screen_Shot_2015-09-21_at_15.00.43.png)


See merge request !1375

This will fix merge problem for merge requests between forks created
before 8.0
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Reported by https://github.com/gitlabhq/gitlabhq/issues/9643

This reverts commit 3abcab77.

[ci skip]

Notification levels can now be set on the Project's main page

![Screen_Shot_2015-09-16_at_7.49.49_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/0ac517bdfdc801f0e2115463c3ea9e10/Screen_Shot_2015-09-16_at_7.49.49_PM.png)

The notification settings for a project can now be set directly on the Project's page. The drop down list and the button label reflect the current level.

Saving is done via a remote form submission and if successful shows the user a flash message:

![Screen_Shot_2015-09-16_at_6.09.02_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/8a6e1fde5177aa3976cadf59fdb8d375/Screen_Shot_2015-09-16_at_6.09.02_PM.png)

@DouweM can you please review my code. I gave my bestest effort to make in clean and readable.

@rspeicher hopefully we can include it with the 8.0 release, maybe?

/cc @darby 

See merge request !1322

Make Markdown area formatting consistent

Issue #2585 


See merge request !1354

Use GitlabCi::VERSION when checking migration



See merge request !1368

CI migration rake task for GitLab CE

- Uses backup format for final GitLab CI 8.0
- Highly optimized tags migration SQL queries


See merge request !1365

Fail ci builds without yml

Fix for https://gitlab.com/gitlab-org/gitlab-ce/issues/2551

See merge request !1349

Fix Markdown links not showing up in dashboard activity feed

Closes #2586

See merge request !1353

Fix reply by email for comments on a specific line in a diff/commit.

Fixes #2363.

See merge request !1364