Changes for legOS-0.1.5:
-------------------------
- added 32 bit system timer with 1ms resolution. Never mind Y2K - we have
  a 49.7 day problem.
- rewrote task switcher to free 8-bit timer 1. Now IR compatible.
- fixed memory management bugs that crashed demos when running them for the
  5th time. (It was the pointer to the first free block. I had conditionally
  defined out the code that updated it. Sigh.)
- fixed IR driver. It seems the carrier has to be turned on exclusively when
  sending, otherwise reception doesn't work. Added fflush() command.
- new demo tm-and-ir.c receives and displays IR at 2400 / 8N1. Broadcasts
  "Hello, world!" messages when view is pressed. Press Run to start/stop.
