fix a few typos in MSRPChat implementation

darcs-hash:20090305161312-b2873-6d0762fa7b5727230bd20a63a81df0ae5fdf27d8
MSRPChat: add is_active and is_started attributes

darcs-hash:20090305161335-b2873-dcb536e34fb8cc51b4172741ea4fd9808a43911d