Split notification handler method of SessionManager into internal sub-methods

darcs-hash:20090205150005-58103-0be40ace4dbaa0208140de386d04e14ad8493269
Simplified state machine of Session object and have it emit SCSessionChangedState notification on locally initiated state changes as well

darcs-hash:20090205173628-58103-7b7d1f3364f8f38ea2cfa32b1be10a7b497a9c34