Merge button has color from CI status
This MR closes#3313
I'am not realy sure about the color for the skipped status (red)...
UI changes:




See merge request !1761
Fix bug where manually merged branches in a MR would end up with an empty diff
This bug manifested in 8.1 with the refactoring of `RefreshService`. Here's what happens:
1. User create a new branch `foo`.
2. User creates a merge request for `foo`.
3. User merges `foo` into `master` by hand.
4. `RefreshService` reloads the merge request. Since `master` is equivalent to `foo`, this results in an empty diff.
5. `RefreshService` then closes the MR.
This wasn't an issue when you use the normal "Accept Merge Request" flow because the act of clicking the button closes the merge request, so step 4 never happens.
Closes#3314
See merge request !1758
Only redirect to homepage url when its not the root url
It was possible to create an infi redirect when the user set up the
`home_page_url` to redirect to the main URL of the gitlab instance.
This fix makes sure this redirect is not possible.
Fixes#1020
/cc @dblessing
See merge request !1703
Spread out runner contacted_at updates
This is meant to prevent having too many concurrent UPDATE requests
caused by runners checking in.
See merge request !1722
Force update refs/merge-requests/X/head upon a push to the source branch of a merge request
If a user rebases and does a force push, GitLab would not update the `refs/merge-requests/X/head` link. Using the -f flag forces this to happen.
Closes#3138
See merge request !1683
Fix cloning Wiki repositories via HTTP
Cloning a project Wiki over HTTP would end up cloning the main repository
since the .wiki extension was being stripped.
Closes#3106
See merge request !1676
Don't show "Add README" link in an empty repository if user doesn't have access to push
Reporter users would see this before even though they didn't have access to push:

It's not complete accurate to include the push command-line instructions, but users may still want the instructions to clone. After:

Closes#3094
See merge request !1626
Animate the logo on hover
The logo is now rendered as pure SVG, rather than image referencing a
svg. The SVG has an id and the shapes of the logo have a shared class.
The shapes change their fill color on hover with a transition.
Identical to how it looks on about.gitlab.com
cc @skyruler
See merge request !1557