Refactored msrp code for clarity and readability

darcs-hash:20090227080445-b22ec-a74adb35c0953c344b4302ff40ceb86d551e3ad1
Changed some MSRPChat attributes from private to public

darcs-hash:20090227082224-b22ec-6a82245c2da41e684c2f16533dc009f9aad00315