Update permissions for issue tracker management

Don't allow guest or reporter to set assignee, milestone and label when create or update new issue and merge request.
After this change `Guest` and `Reporter` rule is used to report issues but only `Developer` and higher roles can manage issues (schedule milestone, assign to user or close any issue)

Also I removed some duplication code between issues and merge requests and put all issuable partials in one directory

See merge request !890

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

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

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

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

Add SAML to list of social_provider

Resolves issue 1888.  Still an issue because the SAML link under Connected Accounts will not have a logo.

See merge request !891

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

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

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

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

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

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

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

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

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

Have sidebar labels disappear behind content instead of hide immediately when collapsing.

I'm not sure how to make a gif out of it, but I promise it looks pretty :)

See merge request !888

prettier highlighting of active link in the sidebar

Before:

![Screenshot_2015-06-25_11.17.08](https://dev.gitlab.org/gitlab/gitlabhq/uploads/851606a122c1d1174d0f97857ad472d3/Screenshot_2015-06-25_11.17.08.png)

After:

![Screenshot_2015-06-25_11.17.42](https://dev.gitlab.org/gitlab/gitlabhq/uploads/b8dc55bcd76dac29652ef5d25f99ccff/Screenshot_2015-06-25_11.17.42.png)

Only with this theme it's not an improvement (this is an honest merge request (trademark pending)) :

![Screenshot_2015-06-25_11.18.35](https://dev.gitlab.org/gitlab/gitlabhq/uploads/5d631a11ee866f5fc51e985b02a836ba/Screenshot_2015-06-25_11.18.35.png)

See merge request !1879

Show a random Markdown tip in the textarea placeholder

cc @darby

See merge request !879

Removed the icons from the New Issue and New Project buttons

Fixes #1869

No more icons!

See merge request !885

Change the default admin password

Closes internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2422

See merge request !865

Performance improvements

* store @participants in variable
* store result of subscribed? call into variable

In total it reduce amount of SQL queries for issue or merge_request with 10 comments/participants almost twice.

See merge request !883

Add 2FA status to user admin API

This MR adds the `two_factor_enabled` field to the admin's API to indicate whether a given user has enabled 2FA.

See merge request !881

Updated merge request merged web hook to correctly fire action=merged.

I believe this merge request will fix both issues #879 and #498.

If a merge request was merged via the command line, the correct web hook was fired with the field `object_attributes.action = "merge"`. However, if the merge request was merged via the web UI, the webhook would be fired with `object_attributes.action = "open"`.

See merge request !780

Fixes #879
Fixes #498

Explicit error when commit not found in the GitLab CI

!!! SHOULD BE MERGED WITH https://gitlab.com/gitlab-org/gitlab-ci/merge_requests/159

https://dev.gitlab.org/gitlab/gitlab-ci/issues/280

See merge request !871

stop jumping all content on collapsing and expanding the sidebar

When you collapse or expand the sidebar, all content shifts with 5px.

This merge request solves that.

cc @darby

See merge request !1877

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

* store @participants in variable
* store result of subscribed? call into variable

In total it reduce amount of SQL queries for merge_request with 10
comments/participants twice.
Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>