Experiments on Arduino with larger register writes and FIFO write ...

Getting some corruption on the Arduino RAM buffers.
Logic analyser traces show that the tables are getting corrupted
and the wrong data is being written to the radio registers.

Implemented most of hrf69.c write and read functions

HRF_write_reg written

Proved that we can read a register back from simulation

First pass at writing a test in hrf69_test.c

First attempt at specing out implementation of HRF69 based on python

Moved all C into a drv folder.