Fix required gitlab-shell version in the 8.5 to 8.6 update doc.

Under the procedure, I've warned about gitlab-shell version, which should be 2.6.12 (may be some minor revisions introduces that).

Added highlight colours to diff rows

Closes #13852

Refactor and expose only Gitlab::UrlBuilder.build(record)

```
$ git grep Gitlab::UrlBuilder

app/models/commit.rb:      url: Gitlab::UrlBuilder.build(self),
app/services/issues/base_service.rb:      issue_url = Gitlab::UrlBuilder.build(issue)
app/services/merge_requests/base_service.rb:      hook_data[:object_attributes][:url] = Gitlab::UrlBuilder.build(merge_request)
app/views/search/results/_note.html.haml:- note_url = Gitlab::UrlBuilder.build(note)
lib/gitlab/note_data_builder.rb:        base_data[:object_attributes][:url] = Gitlab::UrlBuilder.build(note)
spec/lib/gitlab/note_data_builder_spec.rb:    expect(data[:object_attributes][:url]).to eq(Gitlab::UrlBuilder.build(note))
spec/lib/gitlab/url_builder_spec.rb:describe Gitlab::UrlBuilder, lib: true do
```

Fixes #15202.

See merge request !3696

Note form

A lot of the forms have the same actions associated with them so I have created a standard class that encapsulate these actions.

There is also another class that allows toolbar action buttons to be added that will insert different characters based on the HTML `data-prefix` attribute value - this will give us the opportunity to add more actions to the form and maybe create a markdown toolbar in the future.

See merge request !3534

Updated JS spec to include gl_form

Updated the JS to have a standard class with standard actions for each form
Created ability to have toolbar buttons that insert different prefixes dependant upon the data-prefix attribute

Do not require recipients when pusher will be recipient

Closes #10946

See merge request !3603

Closes #13574

API issue update and note create back dating

Closes #14947 

See merge request !3551

Add test for search page

Closes #15222

See merge request !3711

Redis configuration consistency

Related https://gitlab.com/gitlab-org/gitlab-ce/commit/cf669551f69edd66913d22c96cf1de1302e7990e

See merge request !3697

Hide top search form on the search page

Closes #14771

![Screen_Shot_2016-04-11_at_6.04.19_PM](/uploads/44cf2110bad29c0df06d874740a3a61f/Screen_Shot_2016-04-11_at_6.04.19_PM.png)

See merge request !3668

Set tooltips for new added labels

Fixes #15093 

![Screen_Shot_2016-04-11_at_5.50.21_PM](/uploads/52d06f6ccb3ca42e7ce75b94111514c2/Screen_Shot_2016-04-11_at_5.50.21_PM.png)

See merge request !3667

Update delete button

Closes #14762 

![Screen_Shot_2016-04-11_at_5.21.32_PM](/uploads/fef09645eb70fc0fcaee359245664ddc/Screen_Shot_2016-04-11_at_5.21.32_PM.png)

See merge request !3665

Fixed alignment on issuable new form

Fixes #13802

![Screen_Shot_2016-04-11_at_17.03.29](/uploads/d359580e693284d4b694d8158d4f736e/Screen_Shot_2016-04-11_at_17.03.29.png)

See merge request !3661

Updated InfluxDB/Grafana setup/import docs

See https://gitlab.com/gitlab-org/grafana-dashboards/merge_requests/1 for some background info.

cc @dblessing 

See merge request !3706

Clean up ExclusiveLease

See merge request !3695

Fix a bug with trailing slash in bamboo_url

Also, improve specs for BambooService

Similar to !3679.

See merge request !3680

Fix trailing slash in teamcity_url

Originally opened at !2309 by @ctmay4.

As described in #3515, if you have trailing spaces in the the Teamcity server name, the service
will not work properly.  Switching from `URI.parse` to `URI.join` fixes it so that it works with
or without a trailing slash.

Fixes #3515.

See merge request !3679

Load related MRs/branches asynchronously

cc @dzaporozhets 

See merge request !3678

Make milestone labels in labels tab similar to that of the labels page

I realized that some of the changes for the labels page was not reflecting in the labels list in milestone page.

## Desktop
![Screen_Shot_2016-04-11_at_4.25.36_PM](/uploads/e21f3c5a9187fe32472e796171781b5d/Screen_Shot_2016-04-11_at_4.25.36_PM.png)

## Mobile
![Screen_Shot_2016-04-11_at_4.26.47_PM](/uploads/5c9f75ca0938fc30ab47c5520215f692/Screen_Shot_2016-04-11_at_4.26.47_PM.png)


See merge request !3658