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
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
also expire file if timestamp = limit, happens if trashbin_retention_obligation is set to zero
Disable database migrations for MSSQL - scripts have to be applied manually
patch tipsy in style.css - don't patch 3rdparty libraries
simplify mysql user creation flow

if dbuser exists try a different one, owncloud/core#108

changed outdated comment

corrected length calculation

changed indentation for else clauses
Merge pull request #10663 from owncloud/files_trashbin_original_path

Show original path information in trashbin and for shares
Deduplicate dependency checks

Some code that I also used for https://github.com/owncloud/administration/pull/11
Conceal or display SabreDAV version number in browser and http response headers.
Merge pull request #11081 from owncloud/trash_fix_expire

also expire file if timestamp = limit, happens if trashbin_retention_obl...
Merge pull request #11084 from owncloud/no-migration-for-mssql-master

Disable database migrations for MSSQL - scripts have to be applied manua...
Merge pull request #11055 from owncloud/replaceprodname

replace ownCloud with placeholder