Tune commit page: async load of branch info

See merge request !1462

Conflicts:
	config/routes.rb

Update gitlab-shell to 2.4.2 for 7.7 install/update guide

closes #8718, closes #8721

Rubycop improvements

See merge request !1463

Rubocop enabled for: Use spaces inside hash literal braces

See merge request !1461

Ruby hash 1.9 with rubycop check

See merge request !1460

Rubocop

See merge request !1459

Improve project avatars for dashboard

Fixes #1955

See merge request !1457

Make omnibus the default in repo import docs

I hope this reads nicer for people using omnibus packages.

See merge request !1420

Search group documentation

See merge request !1455

Fix RepositoryCache backend attr_reader

Make the structure of spec/models match app/models