Separate rendering of Markdown reference links from redacting those the user doesn't have access to and extracting referenced objects
Related: !1014
See merge request !1090
Track compatible gitlab-git-http-server version
The 'git archive' changes in GitLab 8.1 require a version of
gitlab-git-http-server that is incompatible with GitLab 8.0, so we
need to keep track of this now.
See merge request !1603
Add a system note and update relevant merge requests when a branch is deleted or re-added
If a branch is deleted with an open merge request, amended offline, and then pushed again,
GitLab doesn't bother to update the merge request even though the last commit ID and/or
code may have changed. This MR ensures that each push will update any relevant merge
requests and adds a system note if this happens as well.
The new messages look like:

Closes#2926
See merge request !1601
Also adds a preamble note that a working 8.0 installation (i.e.,
gitlab-git-http-server, updated Nginx/Apache configs) is required before
proceeding.
[ci skip]
Improve invalidation of stored service password if the endpoint URL is changed (V2)
New version of !1583, using the same failproof logic but this time mirroring the name and behaviour of the change-tracking methods of ActiveModel::Dirty in order to make it clearer and more natural.
Added more tests to clarify the expected behaviour.
This is an alternative to !1594
/cc @vsizov @rspeicher
See merge request !1600
Improve User.by_login performance
This greatly speeds up the performance of `User.by_login`. I adopted some changes from @haynes in this patch, the credits go to him for coming up with those originally.
Fixes#2341
See merge request !1545
Let gitlab-git-http-server handle archive downloads
This change relies on changes in gitlab_git and gitlab-git-http-server.
fixes#2429
See merge request !1548
Fix error preventing displaying of commit data for a directory with a leading dot
Directories with leading dots erroneously get rejected by the route controller if git
ref regex is used in constraints. This prevents commit data from being loaded. The regex verification is now done in controller.
Closes https://github.com/gitlabhq/gitlabhq/issues/8763
See merge request !1574
In these particular instances we can just use HAML tags directly. This
can shave off some time spent loading issue pages, though this depends
on the amount of comments being displayed.
When viewing https://gitlab.com/gitlab-org/gitlab-ce/issues/2164 locally
these changes reduce loading time by about 400 ms in total.