Adapted sipsimple/core.ua.pxi to new basic SIP objects

Ignore-this: 651602e0c29c0b98bc27b59d91a14c49

darcs-hash:20090616095040-1e3d8-51c336feff76a94ead70ff8dd66d55d32f6097eb
Adapted RTPTransport and AudioTransport to new basic SIP objects

Ignore-this: 837691cedad6c810bdcf8f34bc82e2e1

darcs-hash:20090616095122-1e3d8-36fed7aa58b668a09945d89bfb793cafe8a9d93b