Added ToneGenerator class to sipsimple.core

darcs-hash:20090629123520-58103-750cac57b2186b534b4497052443350e6bfed888
Modified RecordingWaveFile to use new ConferenceBridge

darcs-hash:20090629123655-58103-1cd9cda161a3f3f61310663a738abfef08910aae