CRAAG2: Reboot RFM every 500 strings instead of 200.
CRAAG2: Move ADC polling code to transmit loop.
CRAAG2: Shorten test tx string.
CRAAG2: Remove $ from string prefix (=>4).
CRAAG2: Reverse high/low.
CRAAG2: Revert: Reverse high/low.
CRAAG2: Fix checksum calculation.
CRAAG2: Set RFM22 SDN as output.
CRAAG2: Add float code.
CRAAG2: Clean up unused variables.
CRAAG2: Add experimental clever gps_get_known_data().
CRAAG2: Fix DGPS bit masking.
CRAAG2: Fix gps_known_data lengths.
CRAAG2: Make all relevant vars volatile.