AP_GPS: added DataFlash to GPS init to allow for detailed logging

this will allow GPS drivers to log much more detailed device specific
information
AP_GPS: added detailed hardware status logging for uBlox

this gives us noise, jamming and RF information from the uBlox
protocol. This will hopefully allow a more detailed investigation of
antenna choices and RF interference
DataFlash: allow drivers to setup their own logging formats

this allows drivers to ask the dataflash driver to add new log formats
AP_InertialNav: fixed example build
VARTest: fixed build
AntennaTracker: fixed build with GPS changes
FollowMe: update for GPS changes
Plane: updates for GPS changes
Copter: updates for GPS changes
Rover: updates for GPS changes
AP_GPS: fixed example builds