Fix searching by extern_uid for LDAP to be case-insensitive

.well-list item name spacing fix Follow up on #6643

Conflicts:
	CHANGELOG

Remove omniauth-ldap nickname bug workaround

Before there was a bug in omniauth-ldap which prevented samaccountname
showing up as a possible username for new LDAP users. Thanks to upstream
fixes, we no longer need to work around this bug.

Invoking 'db:schema:load' turned out to be a bad idea: when downgrading
an existing GitLab installation, the schema of the newer version would
be preserved when trying to import the old version.

Pages affected:
- admin/groups#show
- admin/projets#index
- admin/users#index
- dashboard/issues#index (on small screens)

Update Contribution Guidelines: Specify Merge Request To Master

There have been occasions where contributors submitted merge requests to stable branches thinking that was the way to get changes into specific releases. This results in wasted time and effort of the GitLab team responding to the merge request requesting that it be to master, as well as the developer who needs to redo the changes.

This merge request very simply updates the contribution guidelines to specify that MRs should only be to master, and that getting changes into stable branches will be determined by the GitLab Team.

cc @JobV

Update 6.0-to-6.5.md

Getting-help-on-website

Doc-readme-for-site

New readme files for doc.gitlab.com
I also but the links for the api readme at the top.

Fix another instance of "created at"

Database doc changes to address #2412 and #6451.

Always show merge status

Fix Architecture Img

Image in architecture doc was not showing correctly. Now it is.

Always show the merge status of a merge request, even if the user has no
permission to do the actual merging.

Fixes
http://feedback.gitlab.com/forums/176466-general/suggestions/5673321-everyone-should-be-able-to-see-a-mr-status

Update permissions.md

Fix 500 Error When Creating Issue For Project With No Commits

This merge request fixes issue #153, where trying to create an issue for a project with no commits results in a 500 error. This was done by updating the form to check that the repository wasn't empty before trying to load the contribution guide.

The form was updated to check that the repository wasn't empty before trying
to load the contribution guide.

This fixes #153.

Refactor Parallel Diff feature and add scrollbars

gitlab:ldap:check uses LDAP user filter

Also now removed lines relating to unused comments feature

Check Css

Based on Dmitriy his remark https://gitlab.slack.com/archives/general/p1395770459000142

Case insensitive user search

As per implementation by Christopher Arnold.

Rename Diff to Changes