Add 7+ unit tests

Test array power prediction. Test car caching packets locally
(hephaestus). Test car pushing packets from carside queue to serverside
queue (hermes). Test server receiving/consuming packets. Test
Consumer's handling garbage/nonsense packets. Test Consumer's handling
unrecognized CAN packets. Test Consumer's trashing useless heartbeat
packets. Test DB's initializing temporary row, and timestamping
temporary row.

Update CANUSB test and Task Manager test.

Better handling of SIGINT's, and graceful termination of worker
subprocesses. Moved code style closer to PEP8.

Add (nonfunctional) script to talk to beagleboard.

Server now requires python ≥ 3.3. Since Pika doesn't support Python 3,
we use my translation, github:alexchandel/pika. Expect bugs