UX improvements

* make atom feed on commits page smaller so it capture less attention
* open big image 400px instead of default 40px when click on user avatar

See merge request !910

Fix consistency issue in sidebars of Project and Group Settings.

Fixes #2277

![before_after_group_settings_nav](https://dev.gitlab.org/gitlab/gitlabhq/uploads/370c701d0eff8f1f8e44cf954c75f2bf/before_after_group_settings_nav.png)

See merge request !1871

Repository#blob_at should return nil for 00000000... sha
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !916

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

Reporter role can manage issue tracker now
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !908

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

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

added note about Devise

Added note about the authentication gem used in GitLab

Because of question in https://groups.google.com/forum/#!topic/gitlabhq/G2rToah19-Q

See merge request !912

added new doc "command line commands"

Added new doc to GitLab Basics

See merge request !1880

Performance improvements after caching html fragments

* re-use event cache with other users
* cache commit fragment
* cache issue fragment in list
* cache comment parsed with markdown

See merge request !911

Fix ApplicationHelper specs

On current `master` if you run these specs by themselves, they fail. I have no idea why they work when run with other specs, but now they work all the time.

- Use the `helper` object, as per RSpec 3 standards
- Use `assign` to assign instance variables that helpers expect
- Add `StubConfiguration` support module

See merge request !906

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

Bump Redcarpet to 3.3.2

Closes #1911

See merge request !913

Closes #1911

There were several specs that were failing when run by themselves.

- Use the `helper` object, as per RSpec 3 standards
- Use `assign` to assign instance variables that helpers expect
- Add `StubConfiguration` support module

Just for consistency with our Capybara, DatabaseCleaner, WebMock, etc.
setups.

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>

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

Reuse HTML Pipeline object in Markdown parser

The patches reduces pressure on GC and reduces markdown processing time

See merge request !905

The patches reduces pressure on GC and reduces markdown processing time

Added missing packages required by docker builds

This fixes backup failed tests, missing commands: `pg_dump` and `mysqldump`.

See merge request !889

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

Bump rugments to 1.0.0beta8 to fix C prototype function highlighting

Closes #1890

See merge request !902