Always return local_rtp_address property on RTPTransport

darcs-hash:20090224125836-58103-41aa22fafb3da57bdf22ebf73d2daf9e36d10482
Continue with ICE without STUN if STUN fails for ICE in Session

darcs-hash:20090224125856-58103-b58df18711a91fdf1798bbd346e744d2e1abe660