Added handling for the main window closing.  Any unsubmitted sessions will now be saved to local storage
Cleaned up the playsession definition a bit
If the app is shutdown while scanning, kill the scan
When adding a session less than 30 seconds, the result will now return a 202, indicating acceptance, but nothing else
Overloaded SubmitSession to accept a string.  Also change how submit session works to return back a boolean indicating success to account for changes in the service.  Added the ability to load and submit any unsubmitted sessions from a prior time running the client.