Disable changing of the source branch in merge request update API

As noted in: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/738#note_1307284

See merge request !745

Allow to configure a URL to show after sign out

Split of !669 as requested

This is especially useful with SAML ( !722 ) since the omniauth-saml gem does not support single log-out. This provides a way to log out the user from the SAML IdP after signing out from GitLab.

See merge request !725

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

small typo

See merge request !747

Fix misplaced changelog entry for SAML support

See merge request !746

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

Add ability to leave project
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !744

Support editing target branch of merge request

### What does this MR do?

This MR makes it possible to edit the target branch of a merge request and adds a system note when this happens.

### Why was this MR needed?

Because lots of people requested this feature. :)

### Screenshots

**Edit MR page**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/9b3d405bf7b5f945e35bae3534c2b67b/image.png)

**New MR page**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/3657a2a9efad6d10e8470637d1166bdb/image.png)

**System note**

![image](https://gitlab.com/gitlab-org/gitlab-ce/uploads/cc8066f3d3bdf09c0cce27193210567d/image.png)

### What are the relevant issue numbers?

* Closes https://github.com/gitlabhq/gitlabhq/issues/7105
* See: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/130!

See merge request !738

Add option to disallow users from registering any application to use GitLab as an OAuth provider

Addresses internal issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2264.

![Screen_Shot_2015-05-29_at_13.30.11](https://gitlab.com/gitlab-org/gitlab-ce/uploads/300f8e9ecbeb3d353ebc33a63cdef4e9/Screen_Shot_2015-05-29_at_13.30.11.png)

See merge request !742

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>

User should be able to leave group. If not - show him proper message
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !743

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>

Shorten merge request WIP text.

![Screen_Shot_2015-05-29_at_11.37.46](https://gitlab.com/gitlab-org/gitlab-ce/uploads/5853d9057103bdaacded17798378f68e/Screen_Shot_2015-05-29_at_11.37.46.png)
![Screen_Shot_2015-05-29_at_11.37.49](https://gitlab.com/gitlab-org/gitlab-ce/uploads/be96ee32ab5a8f23835dc37306259b17/Screen_Shot_2015-05-29_at_11.37.49.png)

See merge request !741

Closes https://github.com/gitlabhq/gitlabhq/issues/7105
See: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/130

Add SAML support via Omniauth

Split of !669, with doc

See merge request !722

Include location.search and location.hash in URL for replaceState

Forgot these 😊

See merge request !740

Add Teaspoon for Javascript testing

Looking to expand our Javascript unit tests, and this gem makes things a bit better in that respect.

See https://github.com/modeset/teaspoon

See merge request !715

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

Improve MergeRequest tab-persisting behavior

Now uses the path instead of the hash.

See discussion in !728

See merge request !737

Allow special characters in users bio

Now uses the path instead of the hash.

See discussion in #728.

/:namespace_id/:project_id/merge_requests/:id/commits(.:format)

Remove extra brace

Extraneous curly brace creeped in prior commit.

See merge request !734