Improved TutorClient. Huge refactor. Icon now read from classpath/jar.

Reworked threads, shutdown hook, and exit process to ensure requests are cancelled if student logs/out without cancelling manually.

Converted buttons to labels on panels. Cleaned up 316 panel. Made server auto-detect which panel to use.

Done a whole bunch of stuff: ...

- Added service discovery.
 - Refactored the IMapPanel interface and LabelProcessor to make panels simpler.
 - Numbers now end up in queue label.

Nearly finished.  Need to do testing in labs.