fix in displayNamesInGroup: when specified limit N, we did complex search only in the first N users
fix orientation in image-backend, not in preview system itself
Fixed file list sorting

Now using a natural sort algorithm that is more consistent between JS
and PHP (although not perfect in some corner cases)

- added OC.Util.naturalSortComparator that uses the same algo that was
  used for the user list
- changed user list and files list to use OC.Util.naturalSortComparator
- removed toLowerCase() and changed the comparator to use
  String.localeCompare()
- added unit tests
- added OC_NaturalSort that is used by OCP\Util::naturalSortCompare()
Fixed sort algo for additional cases
Use afterBind to send fileId header for files and directories

afterBind is called for both files and directories and is now used to
send the OC-FileId headers.
change logic in displayNamesInGroup and add some unit tests
Use Doctrine Platform to generate SQL query for table truncation.
Refactor internal session to write directly to $_SESSION
Update AWS sdk to 2.6.15
Fix failing AmazonS3::touch on updated aws sdk
Add a method to get the absolute url for a route

Fix #10926
Append port to trusted domain in case it's not 80 or 443

Ref https://github.com/owncloud/core/pull/10584#issuecomment-54677059
Add unit test

This unit test is shitty but at least it works...
Move select2 from files_external to core
Now using select2 for the groups excluded from sharing
Load select2 on admin page
Remove excludegroup.php

The ajax call is now using ajax/appconfig.php instead
Added select2 on the apps page

Moved setupGroupsSelect() from admin.js to a common settings.js
as OC.Settings.setupGoupsSelect().

Now using select2 as well on the apps page.
Fixed select2 for admin and apps page

Added explicit escaping.
Now internally using a pipe symbol as separator for select2, to make it
possible to use group names containing commas.
fit select2 to ownCloud input style