Reset navigation if sat count is too low.
GPS page on the display to aid GPS outdoor testing.
Fix gps error counter so that it is meaningful, it was being reset each
time the gps unit was reinitialised leading users to think there were no
GPS errors.
GPS - minor code readability improvements.
GPS - adding a fixme regarding 'ap_mode' variable.
GPS - cleanup nagivation reset flag usage.
GPS - Demystify some magic numbers.
GPS - Add packet logging to the OLED display.  Allow autobauding to be
enabled/disabled via cli (disabled by default now).  Fix missing rate
configuration for UBLOX SVINFO which would have resulted in missing
satallite counts.
GPS - adding some documentation.
Update serial port irq handlers so they avoid the % operator.
GPS - more documentaiton updates.
GPS - fix ubox maximum packet size comparisons.  Increase UBlox buffer
size to work with Glonass MSG-SVINFO packets.  Skip data from packets
that are too large to process without attempting to process a large
payout as packet data.  Ignore GPS presence check when enabling
passthrough mode so that it is possible to configure a GPS unit via the
FC without the GPS unit actually having communicated to the FC first.
GPS - quick hack to parse the received GPS data and update the OLED
display in GPS passthough mode.
Optimize uart buffer counter incrementing.
GPS - Update documentation.
GPS - differenciate between timeouts and crc errors.  Improve packet
logging.  Cleanup UBLOX packet parsing.
GPS - handle data loss occurs in the start of a UBLOX frame
SPARKY - Support GPS.

GPS tested on USART1 concurrently with SUMD on USART2, MSP on USART2 and
MSP on USB.  All working as expected.
GPS - handling incoming data as soon as possible to avoid observed GPS
packet loss.
GPS - send UBlox SVINFO only once every 5 cycles (1hz) to reduce load on
the FC.