Prepare ForkService to support forking projects to given namespaces

Remove overload of BaseService.initialize, so initialize gains params,
which is used to pass the namespace (like e.g. in TransferService).

The namespace is checked for permission to create projects in it.
Add Markdown preview to more forms

Enable Markdown previews when creating and editing issues, merge
requests, and milestones, and when editing notes.
Use GET instead of POST for Markdown previews
Refactor Markdown preview tests

Create a new shared module for common issue/merge request behavior,
use `expect` syntax instead of `should`, and avoid `visible: false` in
the `have_css` matcher.
Fix Markdown preview tests

Update Spinach tests for Markdown previews for the new-ish tab UI that
replaced the old preview/edit toggle button.
Add new Markdown preview test

Add a test to make sure that Markdown previews are available when
editing an existing issue.
Fix long line in view
Fix houndci warnings
Fix more Markdown preview tests
Fix test assertions

Make sure we're asserting the correct thing when testing visible and
invisible DOM elements.
Merge branch 'prepare-fork-to-given-namespace' of https://gitlab.com/bkaindl/gitlab-ce into bkaindl/gitlab-ce-prepare-fork-to-given-namespace
Refactor project fork service

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Select namespace where to fork project

Now you can fork project into group or personal namespace.
Also I moved fork logic from ProjectsController to own fork resource

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
fix backup rake task
Routing specs for fork projects

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Improve fork to namespaces feature

* Show namespace thumbnail differently if project was already forked
* Show loading spinner when click on fork
* Fork link navigates to personal namespace only if no manageable groups exists

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
remove duplicate time zone entry in CHANGELOG
remove extra cd command
Merge pull request #8316 from bbodenmiller/patch-1

remove extra cd command
Merge pull request #8310 from bbodenmiller/patch-3

fix backup rake task