change GreenSession to use *args and **kwargs

- fix GreenSession.deliver_message

darcs-hash:20090320105557-b2873-ff9cf950615905150c8842eafdd623762ad8c567
Make accept_proposal accept arguments about which streams to accept

darcs-hash:20090320101625-58103-485e4a88f97999b1c80aad1541c71f3308644f77