Add description to merge request API documentation

See merge request !301

The description can be provided when creating or updating a merge
request.
Signed-off-by: Loic Dachary <loic@dachary.org>

Fix commits pagination

See merge request !1406

Update import doc

Documentation update for #1900

See merge request !1405

Allow to specify home page for non logged-in users

See merge request !1404

Mobile fixes

See merge request !1403

Add support for colored header on Android Lollipop with Chrome

Replace match via get with get on routes

Remove or prepend underscore _ to unused method arguments

Change always passing visible false tests.

Make blob new and edit file editors more uniform

Replace regex methods by string ones since faster and more readable

Simplify SSH fingerprint regexp extraction

Replace highlight.js with rouge-fork rugments

Send checkout sha to services

In case of tags it may be useful to have sha of commit this tag points to.
So now web hooks and services get additional parameter `checkout_sha`

See merge request !1400

Remove password strength indicator

We were having the following issues:
- the indicator would sometimes stay red even if the password that was
  entered was long enough;
- the indicator had a middle yellow signal: what does that mean?
- the red/green backgrounds were not color-blind-friendly.

See merge request !1399

Fix tab index

Fixes #1892

See merge request !1401