Geo: Merge requests on Secondary should not check mergeable status

In a secondary Geo (#76) node, database is read-only. 

If you update your merge request and don't visit the primary node, you would end up with an unchecked `merge_status`.
We should not try to solve that in a secondary node, as this will lead to a 500 error because we can't update data on database.

This MR Fixes that:

```
Started GET "/root/test-project/merge_requests/1" for 189.101.232.69 at 2016-04-28 11:37:28 -0400
Processing by Projects::MergeRequestsController#show as HTML
  Parameters: {"namespace_id"=>"root", "project_id"=>"test-project", "id"=>"1"}
Completed 500 Internal Server Error in 372ms (ActiveRecord: 26.9ms)

ActionView::Template::Error (PG::ReadOnlySqlTransaction: ERROR:  cannot execute UPDATE in a read-only transaction
: UPDATE "merge_requests" SET "merge_status" = $1 WHERE "merge_requests"."id" = $2):
    39:     = render "projects/merge_requests/show/how_to_merge"
    40:     = render "projects/merge_requests/widget/show.html.haml"
    41:
    42:     - if @merge_request.source_branch_exists? && @merge_request.mergeable? && @merge_request.can_be_merged_by?(current_user)
    43:       .light.prepend-top-default
    44:         You can also accept this merge request manually using the
    45:         = succeed '.' do
  app/models/merge_request.rb:122:in `call'
  app/models/merge_request.rb:122:in `block (2 levels) in <class:MergeRequest>'
  app/models/merge_request.rb:272:in `check_if_can_be_merged'
  app/models/merge_request.rb:297:in `mergeable?'
  app/views/projects/merge_requests/_show.html.haml:42:in `_app_views_projects_merge_requests__show_html_haml__3632812159035673711_50958700'
  app/views/projects/merge_requests/show.html.haml:1:in `_app_views_projects_merge_requests_show_html_haml___4126596802437062695_51012840'
```

See merge request !366

Fix MR notifications for slack and hipchat when approvals are fullfiled

A Slack notification comes in after opening a MR about the MR being opened but it also comes in after a MR gets the minimum number of approvers and it uses the same message.

Same behavior is present in hipchat notifications.

Fixes #462

See merge request !325

CE upstream



See merge request !361

Geo: fix Geo::ScheduleRepoMoveService autoload error

While refactoring !354 (Geo: #76) missed class renaming. This will fix:

```
LoadError: Unable to autoload constant Geo::ScheduleRepoMoveService, expected /opt/gitlab/embedded/service/gitlab-rails/app/services/geo/schedule_repo_move_service.rb to define it
```

See merge request !364

Changes support from IE 10+ to IE 11+

IE 11 was released 17 October 2013; 2 years ago. Generally what I have experienced is that support for browsers (when newer ones are available) continues for up to 2 years. Based on that info we would drop support for IE 10 and the latest IE we would support would be IE 11. 

I also think this is more realistic since no one is really testing anything on IE 10 at the moment.  We should start testing on all the browser that we currently support. 

Also we can then have real support for flexbox and not need things like `-ms-flexbox` and other IE specific hacks. 

cc @iamphill @annabeldunstone @elvongray @alfredo1 @rspeicher 

See merge request !3913

Add letter_opener_web gem

Sent emails in the development environment will no longer automatically
be opened in the browser. If a sent email needs to be viewed, it can be
found at the `/rails/letter_opener` route.

See merge request !3893

Add button to toggle whitespace changes

Closes #4271 

**Merge Request**

<img src="/uploads/ea857269faed38a25b63b768d7f3a85b/Screen_Shot_2016-03-23_at_11.32.41_AM.png" width="1157" />


**Diff view**

<img src="/uploads/bc2ac3e4855584f9214c8f3ddf325b06/Screen_Shot_2016-03-23_at_11.32.53_AM.png" width="1211" />

See merge request !3367

Reduce width of parallel diffs

At 50% width the alignment is off on parallel diffs (see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3785/diffs and view in Side-by-Side)  
Reducing width lines them up:

<img src="/uploads/5775d35b0e86397abd10db6195a8a54d/Screen_Shot_2016-04-22_at_2.19.21_PM.png" width="400px">

Also shifted comment button over to center it properly:  
<img src="/uploads/c2468e15bb65523464a941001c3d7298/Screen_Shot_2016-04-22_at_2.24.33_PM.png" width="200px">

See merge request !3891

Increase screen width breakpoint for hide/show discussion

Closes #15606

See merge request !3915

Allow alternative names for the CHANGELOG file.

"CHANGELOG", "NEWS", "HISTORY", and "CHANGES" are recognized as Changelog files.

Also adds relevant tests for each of these names.

Resolves #14864.

See merge request !3768

"CHANGELOG", "NEWS", "HISTORY", and "CHANGES" are recognized as Changelog files.

Also adds relevant tests for each of these names.

Resolves #14864.

Remove devise async

The extra gem isn’t necessary anymore since Devise + Rails 4.2 has ActiveJob integration.

Fixes #15575. Working towards #14286.

cc: @dzaporozhets @rspeicher 

See merge request !3902

Add usage example for the Office 365 GetPersonaPhoto-service.



See merge request !2462

The extra gem isn’t necessary anymore since Rails 4.2 has ActiveJob integration.

Resolves #15575.

Do not fsck projects less than a day old

This should bring the number of false positives down.

Helps https://gitlab.com/gitlab-org/gitlab-ce/issues/15423

See merge request !3926

Fixed width of .search-location-badge as it was causing issues in Safari.

Fixed width of .search-location-badge as it was causing issues in Safari.

Fixes issue #15541 and is a minor CSS only change so [ci skip]

# Before

Safari:
![Screen_Shot_2016-04-24_at_22.35.38](/uploads/74388670fde3af94429d83b954833bd3/Screen_Shot_2016-04-24_at_22.35.38.png)

# After

Safari:
![Screen_Shot_2016-04-24_at_21.59.49](/uploads/177d0d8fda665165dff5006930604fc6/Screen_Shot_2016-04-24_at_21.59.49.png)

Chrome:
![Screen_Shot_2016-04-24_at_21.59.40](/uploads/6764cd5864901210f4f8eff4388fd6db/Screen_Shot_2016-04-24_at_21.59.40.png)

# CSS class referenced in the following files:

`./app/assets/javascripts/search_autocomplete.js.coffee`

`./app/assets/stylesheets/pages/search.scss`

…and is visible on the search bar on every page.

See merge request !3900

Emphasize that GitLab must be partially running when restoring backups.

This caused me a lot of pain until I caught on.
I also enhanced the GitLab Omnibus application data backup restore procedure.  I verified the procedure by executing it with GitLab 8.6.4.

See merge request !3844

Search ui update

Closes #2537 

See merge request !3751