(WIP) Security implementation
Added ContentAdmin Voter
Adapted ContentController
Made AbstractAdmin implement ContainerAwareInterface
Added shortcut for security context service in AbstractAdmin
Corrected doc for security context shortcut
Pass entity to secure method in Content Controller
Corrected datalist shortcut method in abstract admin
Replaced createBuilder / create methods by factory accessor (both for forms and datalists)
Changed default labels for Autocomplete / Entity types
Include bootstrap-tab by default
Trigger changes in form from CKEditor wysiwyg instance