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>

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

Bump rugments to 1.0.0beta8 to fix C prototype function highlighting

Closes #1890

See merge request !902

update documentation styleguide

See merge request !904

Fix wrong order of issues when importing from github

### 1. What does this MR do?

The order of issues imported from GitHub is fixed.

### 2. Are there points in the code the reviewer needs to double check?

Nothing.

### 3. Why was this MR needed?

The default behaviors of GitHub API at listing issues are sort: :created and direction: :desc.

See GitHub API details at https://developer.github.com/v3/issues/#list-issues.

### 4. What are the relevant issue numbers / Feature requests?

Fixes #1791

### 5. Screenshots (if relevant)

Nothing

See merge request !898

Fix Error 500 when relative submodule resolves to a namespace that has a different name from its path

### What does this MR do?

This MR fixes a bug in resolving a namespace when the `name` differed from `path`.

### Why was this MR needed?

The original code was using `name`, when the proper input to `namespace_project_path` was `path`.

### What are the relevant issue numbers?

Closes #1849

See merge request !864

Explain warnings when using omnibus packages with backup restore

Instead of adding this to the omnibus documentation as proposed [here](https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/392), moving to one central place as part of efforts to have central location for the docs.

See merge request !903

Link to SAML docs from doc index

Without this link, the SAML docs are hard to discover.

See merge request !1882

Without this link, the SAML docs are hard to discover.

Attempt to fix the "I should see that I am [un]subscribed" steps

Makes use of Capybara methods that wait. Hopefully this will fix the
random timing-related failures of this step.

See merge request !853

Add Fuubar as the default RSpec formatter

- Shows how many specs have been run, how many remaining
- Estimates how long is left
- Instantly shows failures
- Looks awesome ✨

![Screen_Shot_2015-06-26_at_1.00.47_AM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/da7c989e04237141d9adb4c4b5898359/Screen_Shot_2015-06-26_at_1.00.47_AM.png)

See merge request !893

Add "Requires Input" JS behavior

This aims to replace all of those `disableButtonIfEmptyField` calls littered throughout views and JS with a simple, clean, markup-based behavior.

While going through all of the old usages, I found a few places where the old behavior wasn't actually working, so... bonus, they work now!

See merge request !900

Remove jasmine:ci task, execute teaspoon directly on CI

See merge request !901

Add a troubleshooting section for backup restore docs, explain about warnings when using omnibus packages.

Closes #1890

See API details at https://developer.github.com/v3/issues/.
Refs #1791

The "Begin with the selected commit" checkbox requires the submit button
to be enabled, even if the extended SHA1 input field is blank.

These have been replaced by the "requiresInput" behavior.

Rename abilities to correspond contoller/model action names

write_ was renamed to create_
modify_  was renamed to update_

So now in update action we have next code

```
def create
  can?(current_user, :create_issue, @issue)
end

def update
  can?(current_user, :update_issue, @issue)
end
```

See merge request !896

Reorder MergeRequestTabs constructor

The tab was being activated before we set the `[commits|diffs]Loaded`
variable, so even when the `/diffs` route is accessed directly, like
from the "Side-by-side" link, the tab was being loaded from its default
source.

Fixes #1887

See merge request !892

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