tport_type_udp.c: when binding to multicast address, join to the group, too.
tport_type_udp.c: when binding to multicast address, join to the group, too.

Use "canonic" IP address (from host-part of the SIP URI) to specify
interface.

darcs-hash:20080103170839-65a35-febd17b39ae4db5d5d4ab707780c33d3a69fa4e8.gz

unispeech/sofia-sip,jart/sofia-sip,jart/sofia-sip,BelledonneCommunications/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,xhook/sofia-sip,jart/sofia-sip,erdincay/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,BelledonneCommunications/sofia-sip,unispeech/sofia-sip,xhook/sofia-sip,erdincay/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,BelledonneCommunications/sofia-sip,xhook/sofia-sip,xhook/sofia-sip