Count number of CRC errors.
Restore main.c copyright notice.
Update libswiftnav and use SBP utils functions for solution output.
Merge branch 'master' of github.com:fnoble/piksi_firmware into chibios
Move solution output code into its own file.
Move tracking channel selection logic into its own function.
Add hysteresis to channel inclusion logic.
Formatting
Update CPU usage monitoring to use DWT cycle counter.

Previously sampling current thread on system tick which could sometimes sync up with the NAP ISR and make it look like the NAP ISR was using 100% CPU, this should be much more accurate as it measures every context switch.
Move solution code into solution.c