Option to use the IP address found in REGISTER response in the SDP

[bennylp]

pjsua_acc_config.allow_sdp_nat_rewrite:

This option controls whether the IP address in SDP should be replaced with the IP address found in Via header of the REGISTER response, ONLY when STUN and ICE are not used. If the value is FALSE (the original behavior, and the default value), then the local IP address will be used. If TRUE, and when STUN and ICE are disabled, then the IP address found in registration response will be used.