dn needs to be fetched to be able to detect memberOf support
Close the session for preview generation

Without closing the session every preview image generation is locking the session which makes the webinterface unresponsive.
don't clean up the test environment if a data provider was finished
Add flock to config

This adds a file lock to the config in hope that this prevents race conditions as reported in https://github.com/owncloud/core/issues/11070

Testplan:

- [ ] Delete config.php and make it read-only => Error is thrown that it is not writeable
- [ ] Installation still works
- [ ] Changing config settings works (i.e. using the SMTP config switches in the administration menu)
- [ ] Your PC didn't blow up
- [ ] Installing the news app and the "Disable AppCode checker" app did not destroy your installation

Only skip the main config

Otherwise read only additional configs might not be processed

Test on tmpdir
Use SVG previews for public sharing

Fixes https://github.com/owncloud/core/pull/11367#issuecomment-57306037 and https://github.com/owncloud/core/issues/9218
Redirect only to absolute URL

We do not want to redirect to other domains using the "?redirect_url=" feature. Please notice, that the ownCloud project does not consider open redirectors as security issue.
Fix AmazonS3 rmdir on the root
Fix amazon s3 rename overwrite
Fix copy overwrite for amazon s3
Skip test for unsuported feature for amazon s3
log exceptions when listing files
folder size and mtime is always unknown in s3
more s3 fixes
make rescanDelay of root dir configurable, add on the fly update of legacy storage ids, !isset -> empty when checking strings
make some storage tests explain what went wrong
strict comparison
reduce number of http calls on remove and rmdir
fix typo