introduce a new ticket-active class and add status

This makes it possible to style active ticket links different and
also style ticket links by status.
Pass the role type to the ACL method, as AddRoleMember does

This caused failures in removing watchers from tickets and queues, when
the remover only had Watch / WatchAsAcminCc; see [rt3 #29063]

This is now also consistent with how all existing _HasModifyWatcherRight
methods (the only functions currently passed for ACL) expect to be
called.
Document the ACL argument, as AddRoleMember does
Merge branch '4.2/ticket-status-in-link-class' into 4.2-trunk

Conflicts:
	share/html/Elements/ShowLink
Merge branch '4.2/remove-role-acl' into 4.2-trunk