[libcommhistory] Improve event states for MmsHelper receive and cancel methods

Set the Waiting state immediately when initiating download for better
interactivity. Also set the ManualNotification or TemporarilyFailed
states (for receive and send respectively) immediately on cancel.
Merge pull request #79 from special/mms-event-states

[libcommhistory] Improve event states for MmsHelper receive and cancel methods