Tue Jun 12 11:50:14 EDT 2012

Things to change

- cache the PIC18 target code generation in the Racket compilation
  phase, it is very slow.  I.e. once the module code is fixed, there
  is no reason to run the macros more than once: result will be the
  same, so just store the target code in the module and wrap this in a
  Racket compilation phase.

- decouple PK2 driver from interpreter image, I.e. provide over TCP.
  This could even be written in C to allow it to run on a larger uC.