Use a Teensy, instead of an Arduino.

The Teensy++ 2.0 is smaller, has more IO, more of all types of memory,
and a 0.1 inch footprint.  It uses an 8 bit AVR, similar to the
Arduino.

http://www.pjrc.com/teensy/

This only duplicates the current feature set.  Adding features comes
later.

There are (unfortunately) other changes in here:

- Addition of morse code assertions.  This was needed when the LCD
  didn't initially work.

- Change in QP-nano initialisation, keeping interrupts off until
  QF_onStartup().  The proper way is to enable the peripherals early,
  keeping the peripheral interrupts off but global interrupts on, then
  enable the peripheral interrupts after all the AOs are initialised
  in QF_onStartup().

- Change in serial_drain(), to do polled sending if interrupts are
  off, or interrupt driven sending of interrupts are on.  This was
  necessary because of the interrupt change above, and should be
  reverted when the interrupts are initialised properly.

- Sending initial timer events, from inside initial transitions, with
  QActive_postISR() instead of QActive_arm().  This is another change
  necessary because of the interrupt change, and should also be
  reverted.

Signed-off-by: Russell Steicke <russells@adelie.cx>