fix initial loading limit of user management on large screens
Send mail for new users

* supply mail address
* send mail with username and URL to that mail address
* option to temporary enable this feature
add unit tests for new user create mail
fix alt text for breadcrumbs home icon
properly name form labels for the file selection
add text to Delete action
add empty alt text for user image
fix Delete action text being translatable
add alt text to 'Cancel upload' button
add text to Settings button
Move the Null-Byte LDAP check to the user manager

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
use method to only visually hide elements, show only for screen reader
add label for search field for screen readers
Movable mountpoints are always deletable
Root always exists
HHVM: Call libxml_use_internal_errors() instead of surpressing errors.

In contrast to the previous solution, this also works on HHVM.
add a isLoggedIn method to the usersession and deprecate the isLoggedIn method on the api
use two tests instead of one
fix tests
add isAdmin and isInGroup methods for the group manager