Check if local_ip argument is IPv4 address when starting engine

darcs-hash:20090303172049-58103-1c052a26cd35cbfe2fb602440907f4172024564f
Updated so-called "bonjour" functionality in sip_audio_session.py

darcs-hash:20090303174110-58103-54fe8657ab685681f8adae403e9b232663aeb210