FIX: Album is now also linked by title
FIX: Contentidentifier can not only by a number - the content element uid is now prefixed by a c
DEL: Unused viewHelper AlbumAdminViewHelper
FEATURE: The download link beneath single images now sends the file as download while protecting it from grabbing the whole database
Merge branch 'develop' of github.com:YAG-Gallery/yag into develop