Make the first branch pushed to an empty repository the default HEAD

In an empty repository, pushing a new branch not called "master" would leave HEAD in an unknown state, causing ambiguity if another branch were pushed. This could in turn cause a new protected branch to be created and cause the default branch to change.

* Closes #1561
* Closes #1576
* Closes https://github.com/gitlabhq/gitlabhq/issues/8883

See merge request !614

revert bad link in documentation

See merge request !1808

Added link reset root password

Added text to link "How to reset root password"

cc/ @sytse

See merge request !1799

Add Markdown feature specs for markup inside links

It was already working, just want to make sure we don't break it in the future.

See merge request !619

It was already working, just want to make sure we don't break it in the
future.

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

Refactor mr form

* re-use issuable form for new mr page
* small UI improvements to MR compare and new pages

See merge request !616

Small UI improvements to make project sidebar more neat

* make sidebar blocks more compact
* make clone panel smaller for better aspect ratio
* make `forked from` section cleaner

Screenshot:

![Screenshot_2015-05-06_16.42.12](https://gitlab.com/gitlab-org/gitlab-ce/uploads/69723db619ae7ae4d9551f6340d45384/Screenshot_2015-05-06_16.42.12.png)

cc @rspeicher

See merge request !617

Single docker image

See merge request !1805

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

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

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

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

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

Allow to configure smtp and sendmail in gitlab.yml

When use change branches link at MR form - save source branch selection instead of target one

Fix for https://dev.gitlab.org/gitlab/gitlabhq/issues/1800

cc @jacobvosmaer

See merge request !615

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

Fix a trailing new line

The "How to Merge" modal included a trailing new line in the code
block. This commit removes that disfigurement.