Implemented xbh git revision command

Also added ntoa as a dependency in utils.[ch]

Reorganized some makefile defines
Moved priorities to seperate files

Also relocated startup_gcc.c since hardware-specific
Cleanup, added unk to xbh_prot
Moved cpu freq constant to hal.c
Header include organization
Added timer measurement code
Work on measurement functions.

Trying to get wraparound to work w/o issues w/ race conditions
wip on measuring power
Added macros to make ISR priorities ascending

Note that ARM priorities are descending, i.e. higher priority tasks have lower
numbers. Also, only the upper 3 of 8 bits are considered.
This makes them consistent w/ FreeRTOS priorities.

Also Reordered functions in hal/lwip_eth.c and removed setup call in hal.c
Figured out algorithm for timer wraparound

Avoids extra counts in event of a race condition w/ wrap and capture ISRs
Also started work on power sampling