Don't allow page to be scaled on mobile and add horizontal scrolling to code blocks

Closes #1974.

Previously, scaling (both automatically and manually) was enabled on mobile, which caused the top and sidebar to move over content. Scaling is now disabled.

Also previously, code in issues or comments too wide to fit inside the width of the window would "flow out" on the right, causing the whole page to become very wide and causing scrolling to scroll the entire page instead of just the code. Code blocks now scroll themselves.

See merge request !1501

Actually submit comment on command-enter.

Resolves #1869.

Because !1474 didn't actually work.

cc @sytse

See merge request !1499

Resolves #1869.

Bump gitlab shell

See merge request !1497

Add label notes

It creates system note, when someone changed labels of issue/MR.

Just look at the screenshot:

![labels](https://gitlab.com/uploads/vernik91/gitlab-ce/ebbdba6bdc/labels.png)

Solves this [request] (http://feedback.gitlab.com/forums/176466-general/suggestions/6623258-create-a-note-when-issue-labels-change).

*P.S. Thanks this [PR](https://github.com/gitlabhq/gitlabhq/pull/8237) for idea 😉. But I need this feature as soon as possible.*

See merge request !331

Extend issue clossing pattern

New: "Resolve", "Resolves", "Resolved", "Resolving" and "Close"

Now matches those supported by [GitHub](https://help.github.com/articles/closing-issues-via-commit-messages/), with the addition of the -ing forms.

See merge request !1475

Cleanup gitlab example

Fixes #1938

See merge request !1495

Add internal broadcast message API.

See gitlab/gitlab-ee#241.

Used by gitlab/gitlab-shell!53.

See merge request !1486

Add index on order columns for services table

See merge request !1492

Bug fix for default issue tracker

See merge request !1493

Changelog description

Please merge before tomorrow.

See merge request !1491

Improve release guides

* move update docs to separate file to prevent mess with rc tasks
* update patch release guide
* update GitLab.com when packages are done. No need to wait 2 days

See merge request !1490

Improve OAuth UX

See merge request !1489

Added a note saying inline HTML is disabled by default

Add Asana service

Be less restrictive on key comment extraction

Addex X-GitLab-Project header to GitLab emails.

Fix project sidebar overflow small screens

See merge request !1488

Autosave and autorestore unsaved comments.

Closes #1738.

See merge request !1480

Conflicts:
	db/schema.rb

Add "Import all projects" button to GitHub and GitLab import pages.

Closes #1963.

See merge request !1482

Merge branch 'fix_showing_overflow' of https://github.com/duduribeiro/gitlabhq into duduribeiro-fix_showing_overflow