Allow for setting a edit_cancel_redirect
Defaults to list view for the entity but can be overriden by setting
the parameter manually. Falls back to history.go(-1) if not set.
Patch by: Sverre Rabbelier
Also flush the user's ACL's when flushing the sidebar
It is pretty pointless to flush the sidebar if the same ACL's will
be re-used anyway, so make sure the ACL's are flushed as well.
Patch by: Sverre Rabbelier