Merge remote-tracking branch 'Mavlink/master' into iosAppStore

* Mavlink/master:
  Improving coding style
  Updating mavlink v1.0 ref
  Removing AndroidJoystick (requires Qt5.6)
  GPSFact.json: add RTK float & fixed types
  gps: use a read buffer size of 1024
  gps: update drivers submodule
  gps read callback: avoid sleep, don't wait when data already available
  gps: use GPS_RTCM_DATA mavlink message for RTCM, use fragmentation if needed
  gps: update submodule
  gps: use an inline function for usleep instead of #define
  GPSProvider: add SIMULATE_RTCM_OUTPUT to enable simulated RTCM output (currently disabled)
  Sync with official
  Fixing syntax
  Android Joystick support
  Fixing syntax
  Android Joystick support
  Fixing syntax
  Android Joystick support