-ensure the TransportSelector will not have a need to delete transport pointers after they are already handed
 back to the caller.  SipStack now tracks lists of transports in order to avoid needing to query
 TransportSelector and require locking
-complete dynamic removal of transports by ensure we back out things that were done during the add
 -SipStack::mPorts and SipStack::mDomains - now using reference counting

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@11012 ddefafc4-47db-0310-ae44-fa13212b10f2