Upgrade to Sidekiq 3.3

Fixes #1807.  Upgrades Sidekiq to the latest stable release.

cc @sytse

See merge request !1419

Append in place for strings and arrays [failure unrelated]

Validation of 'Create branch' and 'Create tag' buttons

Fix various typos

Conflicts:
	CHANGELOG

Disable 'check all issues' checkbox for unprivileged users.

Fix spinner icon to match others

Fix sentence in notification page

Correct the sentence in profile notification settings page.

/cc @jacobvosmaer @dzaporozhets

See merge request !1421

Remove unnecessary / from avatar url

## What does this MR do?

This MR removes the unecessary / from the avatar url.

## What Use Case does this MR solve?

The // in the url cold lead to avatars not being displayed (reported on IRC)

With this MR the avatar url changes from
http://localhost:3000//uploads/user/avatar/1/gitlab_logo.png
to
http://localhost:3000/uploads/user/avatar/1/gitlab_logo.png

@dblessing Can you take a look?

See merge request !303

show diff in submodules

Allow commit messages to close several issues at once

Show tags in commit view

### What does this MR do?
With this MR you can see the assigned tags for a commit in the commit view.
### Are there points in the code the reviewer needs to double check?
I don't think so. But it would be awesome if the reviewer can tell me how to add a tag to the sample_commit in spec/support/repo_helpers.rb.
Then I can add a test for the new tag_names_contains method as soon as possible :)

### Why was this MR needed?
At the moment if one click on a commit will see details such as: parent commit, amount of additions, deletions, but will not see if this commit has Tag linked to it.
Showing branch, tag details will give better overview about the commit

### What are the relevant issue numbers / Feature requests?
Feature request: http://feedback.gitlab.com/forums/176466-general/suggestions/3962044-show-tags-in-commit-view
### Screenshots
![gitlab_feature_show_tags](https://gitlab.com/uploads/haynes/gitlab-ce/771c1a36bb/gitlab_feature_show_tags.png)

@dblessing Can you take a look at this MR as well please?

See merge request !297

Developer can push to protected branch if allowed

#1876

See merge request !1418

Github importer: AJAX update status

#1907

See merge request !1417

Add action property to merge request hook

for his work and help)

Github importer feature desc

@job Can you take a look?

See merge request !1414

Border radius fixx

Fixes the border radius in the description box.

See merge request !1416

print validation errors when gitlab-rake gitlab:import:repos fails for project

Currently, when gitlab-rake gitlab:import:repos is not able to import a project it justs prints "Failed trying to create project" to the console. There seems to be no way to find out what exactly has failed. Since the check uses validation, it should at least print the validation issues. That might be a bit cryptic, but may be better than leaving the user in the dark completely.

See merge request !147

Fix the email variable substituation in ssh help page

Update doc github importer.

See merge request !1413

Update doc github importer

See merge request !1412