The command-line tool is now mostly functional.  It can't verify yet
though.

Now the code has been split into several files to keep things better
organized.  Chip definitions are in chips.py, exceptions are in
exceptions.py, and LPC and friends are in lpc.py.  __init__.py has a new
function that provides the best way to create an LPC object, handling
all the boring bits of control, synchronization, and changing the type.