Add a firmware config for functional testing.

Fixed #280.
Add a test suite for checking basic control commands on a programmed VI.
Add functional tests for sending and receiving CAN messages.
Allow setting UART logging status via fabfile.
Add software CAN acceptance filtering for LPC17xx.

Fixed #295.
DRY up checking CAN messages in functional tests.
Organize functional tests into classes.
Test receiving simple vehicle messages in functional tests.
Catch errors when sending diagnostic requests.
Use better name for vehicle interface object in tests.
Add functional test for sending a diagnostic request.
Add functional test for receiving a diagnostic response.
Add functional test for calcuating value of known OBD-II PID.
Add tests for creating and cancelling recurring diag requests.
Reduce noisy output when running compile tests.
Make sure func tests run from root directory.
Add a func. test for sending and receiving extended CAN frames.
Move commands to a subdir and split into mutiple files.

The commands file was getting too large.
Add a command to enable and disable the CAN AF while running.

Fixed #301.
Add a command to change payload format while running.