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

Allow dashboard and group issues/MRs to be filtered by label

See merge request !1591

Use gitlab-git-http-server 0.3.0 for GitLab 8.1

See merge request !1605

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

Improve typography



See merge request !1622

Dont put padding on typography but on holder elements instead

Fixes wrong padding of wiki content.

See merge request !1620

Make selectbox options more compact
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !1619

Highlight comment based on anchor in URL
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix for #2954 

See merge request !1618

Add index on ci_commits.gl_project_id



See merge request !1616

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:

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/6581eea069cd8e485b7fa4187ed4c043/image.png)

Closes #2926 

See merge request !1601

Implement when syntax in .gitlab-ci.yml

See merge request !1606

[ci skip]

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]

[ci skip]

Sentences end in periods.

[ci skip]

See merge request !1604

Prepare 8.1 documentation

[ci skip]

See merge request !1612

Update redcarpet gem. Fixes gem memory leak

Fixes #2773 

See merge request !1607

Build View UI fixes



See merge request !1608

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Markdown typography CSS fixes

The `!important` flags recently added to the `md-typography`
mixin's `pre` elements were overriding the background and
foreground colors for syntax highlighting.

| Before | After |
|:------:|:-----:|
| ![Screen_Shot_2015-09-25_at_3.32.32_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/802163bd9f46864ac89e7be165951f07/Screen_Shot_2015-09-25_at_3.32.32_PM.png) | ![Screen_Shot_2015-09-25_at_3.33.30_PM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/6be72036653378405320085324dff5ad/Screen_Shot_2015-09-25_at_3.33.30_PM.png) |

See merge request !1442

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

Added builds view

![Screen_Shot_2015-10-13_at_19.02.48](https://gitlab.com/gitlab-org/gitlab-ce/uploads/95bb3a7d9d603678fdd077558637045d/Screen_Shot_2015-10-13_at_19.02.48.png)

/cc @dzaporozhets @vsizov 


See merge request !1593