AP_GPS: SwiftNav RTK Driver and GPS AutoSwitch param
ArduCopter: GPS Callback for calculating base position
MAVLink: New message definitions for GPS_RTK
MAVLINK: Recompiling Headers
GCS_MAVLink: Add support for GPS_RTK messages
AP_GPS: GPS calculates MAVLink messages for GPS and GPS_RTK
ArduCopter: Move MAVLink size check into library