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 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
Merge branch 'master' of https://github.com/owncloud/core
Preserve transparency when loading from a file

Fix #7148 - again :)
use intl's native normalizer_normalize() in case the module is available
Step one, open guest layout for different styles.

Conflicts:
	core/templates/layout.guest.php

Step one, open guest layout for different styles.
remove icon styles from apps.css as they are in icons.css
use same shade of grey for active navigation items and hovering
Show original path information in trashbin and sharing views

Path will only be shown if in subdirectory, not in root.
Better tooltip handling of very long strings

 * Maximum tooltip length now 400px instead of 200px
 * Overflowing strings create ellipsis (...)
replace ownCloud with placeholder
remove obsolete language files
remove bottom: 0 to prevent the menu form overlapping the whole element. This happens if a folder has entries, the menu expands to the very bottom and overlaps all entries and makes them impossible to click

fix input width which was changed likely with the icon PR

use calc because firefox and chrome have different scrollbar widths which causes firefox to push the button into the next row while everything is well in chrome

add normal width for IE8
also expire file if timestamp = limit, happens if trashbin_retention_obligation is set to zero
Add timeout to user and group deletion notification

Added timeout in DeleteHandler to auto-delete after a delay.

Fixed issue where OC.Notification.hide() was called twice in a row when
deleting multiple entries, causing the second notification to disappear.
Fixed issue where "undo" click event handler was registered multiple
times when calling setNotifications() twice.
Added JS unit tests for the DeleteHandler class.

Refix undo users, groups feature

Timeout is now cleared in cancel().

Fixed click handler name for "undo" to be able to work with multiple
DeleteHandler instances (in our case one for users and one for groups)
so that there is no conflict.
Merge pull request #10960 from owncloud/use-intl-module-master

use intl's native normalizer_normalize() in case the module is available