Have ConferenceBridge use PJSIPUA dealloc handler

darcs-hash:20090722161744-58103-eec8783228e4bcf052b848042ccda94203749986
Fixed ConferenceBridge idle bug for Mac

darcs-hash:20090723080923-58103-1afb6c8fe2e9655407f32de12b66da34ba11203f