fix initial loading limit of user management on large screens
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
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
HHVM: Add workaround for missing Memcached::deleteMulti()
Move basic auth login out of `isLoggedIn`

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
Store result of authentication
even better empty state for Favorites, and general Empty State style
use empty state for 'Shared with you' as well