Added settings to use MSRP alternative connection model

Ignore-this: 457b44fc44da984dadefcfb754a9a3cc

darcs-hash:20100525135413-58252-ed9f8ec126d619c695cfb69592e50e48b1037057
Only accept IP addresses for the STUN server list

Ignore-this: 4fce738472fc38c03ce88bd19a460fad

darcs-hash:20100525153348-56b4d-57c03ae82fcb7642b4d880021124437ecfa36dc9