Change default codec list to have G722 as first choice

darcs-hash:20100728103824-58252-d3b13f56284c9a949020f1db1d3427ac6cc7fbb8
Fixed handling of case when session is ended before INVITE is sent

Ignore-this: ff0ce46b3c2af713796fbf133c23f737

darcs-hash:20100809084425-1e3d8-b9b011079931f90115cf2ea3ad37e6a4642e0300