removed content-plugin

"old" code of categories-delete is back so it's removed.
altered CB-myattending
altered CB-MyEvents
altered finder plugin
altered mailer
altered Search-plugin
little cleanup edit-event (front)
little cleanup venues (backend)
added event-trigger (eventedited) to event-controller
altered event-page (front)

removed obsolete code, disabled double meta-keyword setting, moved
meta-description outside the function.