fix initial loading limit of user management on large screens

Move the Null-Byte LDAP check to the user manager

HHVM: Add workaround for missing Memcached::deleteMulti()

More accessibility fixes for Files

Improve empty states

Move basic auth login out of `isLoggedIn`

Setup a docker container that holds a webdav instance to test files_exte...

document docker parameter and use random host port
fix typo
copy autotest.sh to autotest-external.sh
adds ability to add start* and stop* scripts in env in external tests
run files_external WebDAV tests against ownCloud instance
introduce executor number to be able to shut down the correct docker container
fetch docker images in advance - this also fetches latest versions of the docker images
add second argument to autotest-external.sh which can specify a single test to run
print out the explicit test run
change naming schema of files_external setup scripts

Add isAdmin and isInGroup methods for the group manager

HHVM: Call libxml_use_internal_errors() instead of surpressing errors.

Potentially fixes https://github.com/owncloud/core/issues/12915 and opens the door for potential other bugs...

Please test very carefully, this includes:

- Testing from OCS via cURL (as in #12915)
- Testing from OCS via browser (Open the "Von Dir geteilt" shares overview)
- WebDAV
- CalDAV
- CardDAV

Add the storage id to the mount config

Propertly restore thumbnail on cancel/rename/move

In contrast to the previous solution, this also works on HHVM.

polish the Favorites design

Since the thumbnail is now in a div, the code that tries to change the
thumbnail have been adapted here as well.

The existing method is deprecated and just a wrapper around the manager method. Since in the future other code paths might call this function instead we need to perform that check here.

Related to http://owncloud.org/security/advisory/?id=oc-sa-2014-020