Improve MergeRequest tab-persisting behavior

Now uses the path instead of the hash.

See discussion in !728

See merge request !737

Now uses the path instead of the hash.

See discussion in #728.

/:namespace_id/:project_id/merge_requests/:id/commits(.:format)

Remove extra brace

Extraneous curly brace creeped in prior commit.

See merge request !734

Make user settings account page nicer

* make 2 factor auth section `panel-default`
* make oauth buttons smaller
* remove primary button from reset token form

![Screenshot_2015-05-28_20.37.30](https://gitlab.com/gitlab-org/gitlab-ce/uploads/e536723e087b72a5c08b29072fb4972f/Screenshot_2015-05-28_20.37.30.png)

See merge request !733

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

Use panels instead of well for widgets in project sidebar

Cleaner look and less distractive

![Screenshot_2015-05-28_17.31.27](https://gitlab.com/gitlab-org/gitlab-ce/uploads/d4f8e58f76c7f62c488dd571c313e21e/Screenshot_2015-05-28_17.31.27.png)

See merge request !732

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

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

Conflicts:
	app/views/profiles/accounts/show.html.haml

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

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

You can not remove user if he/she is an only owner of group

To prevent loose of group data you need to transfer or remove group
first before you can remove user
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !730

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>

To prevent loose of group data you need to transfer or remove group
first before you can remove user
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix git blame syntax highlighting when different commits break up lines

### What does this MR do?

This MR fixes a bug where syntax highlighting would not work properly in certain lines when doing a `git blame` view of a file. Also, this MR reuses the Rugments lexer and formatter for each `git blame` commit block, which should make things faster and reduce overhead.

### Why was this MR needed?

When doing a `git blame`, GitLab feeds the Rugments lexer/formatter blocks of code based on the latest commit for each line.  However, this can cause lexer to fail because the state is cleared between each block of code, which causes `highlight` to fallback to the plaintext lexer. For example, notice this unhighlighted line in [this file](https://gitlab.common-lisp.net/cmucl/cmucl/blame/master/src/assembly/assemfile.lisp):

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/b403fe5c2b883882a9eeea7e0409c583/image.png)

The fixed version looks like this:

![image](https://gitlab.com/stanhu/gitlab-ce/uploads/32c4d7c8ff15a7d59b364dd988f7c657/image.png)

This MR requires a patch to rugments to allow the `continue` option to be passed to the lexer.

* https://github.com/rumpelsepp/rugments/pull/24
* https://github.com/rumpelsepp/rugments/pull/23
* Also submitted to rouge: https://github.com/jneen/rouge/pull/267

### What are the relevant issue numbers?

Closes #1521

See merge request !697

update changelog for 7.11.4

See merge request !1833

[Documentation] non-omnibus instructions for changing time zone

Some language improvements

Persist current merge request tab selection via URL

Closes internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2350

See merge request !728

Change some header icons

icons changed:

* profile settings: user icon to cog
* admin area: cogs to wrench

Based on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/719#note_1289290

![Screenshot_2015-05-27_17.58.12](https://gitlab.com/gitlab-org/gitlab-ce/uploads/762de4afb8ae229a96ead8b2d213b2a4/Screenshot_2015-05-27_17.58.12.png)

See merge request !726

Disable Unicorn::WorkerKiller in non-production environments

Addresses internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2281

See merge request !729

Closes internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2350

Closes #1521

Add ExternalLinkFilter to Markdown pipeline

Forces a `rel="nofollow"` attribute on all external links.

Addresses internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2314#note_46525

See merge request !727

Forces a `rel="nofollow"` attribute on all external links.

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

Fix milestone "Browse Issues" button.

After refactoring around issue/merge requests filters, the button stopped working :(

See merge request !699

Fix project snippets button appearing when it is disabled

There was a typo in 9bcd3639 that caused the project snippets option to be shown when it is disabled.

Closes #1705

See merge request !720