Also fix a number of issues where author/reporter names were not available.

This adds some duplication, but this helper is temporary.

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

This module is now the sole source of knowledge for *how* we render
Markdown (and GFM).

Update PreferencesHelper specs

Instead of rendering this value server-side, we use Javascript and Gon
to apply the user's color scheme (or the default) to any syntax
highlighted code blocks.

This will make it easier to cache these blocks in the future because
they're no longer state-dependent.

Very similar to Gitlab::Theme, this contains all of the definitions for
our syntax highlighting schemes.

Closes #2340

and request them each session. Pass these tokens to the project import data.

This prevents the need to encrypt these tokens and clear them in case they
expire or get revoked.

For example, if you deleted and re-created OAuth2 keys for Bitbucket, you would get
an Error 500 with no way to recover:

```
Started GET "/import/bitbucket/status" for x.x.x.x at 2015-08-07 05:24:10 +0000
Processing by Import::BitbucketController#status as HTML
Completed 500 Internal Server Error in 607ms (ActiveRecord: 2.3ms)

NameError (uninitialized constant Import::BitbucketController::Unauthorized):
  app/controllers/import/bitbucket_controller.rb:77:in `rescue in go_to_bitbucket_for_permissions'
  app/controllers/import/bitbucket_controller.rb:74:in `go_to_bitbucket_for_permissions'
  app/controllers/import/bitbucket_controller.rb:86:in `bitbucket_unauthorized'
```

Closes #1871

I also revamped the tests on "closing reference commits" (= "Fixes #xxxx" for example).
Now, there are two different contexts:
- when the commits with "closing reference" are pushed to the default branch,
- when the commits with "closing reference" are pushed to a non-default branch.

Closes gitlab-org/gitlab-ce#2190.

This was broken in 70f52918 as a result of introducing the ability to filter by current user.

Closes #2320

Only show recent push event if the branch still exists or a recent merge request has not been created

Closes #2277

Closes #2305

Gracefully handle SMTP user input errors (e.g. incorrect email addresses) to prevent Sidekiq retries

Closes https://github.com/gitlabhq/gitlabhq/issues/9560