OP-1273 New files for the MS4525DO PixHawk speed sensor: PIOS files and module files
OP-1273 attitude estimation uses airspeedSensor.TrueAirspeed when available (e.g. from MS4525DO; available when TrueAirspeed >=0 ) instead of using an altitude correction IAS2TAS(alt). When not available it falls back to IAS2TAS(alt)
Merge branch 'andrecillo/OP-1273_PixHawk_airspeed_sensor_MS4525DO' of ssh://git.openpilot.org/OpenPilot into andrecillo/OP-1273_PixHawk_airspeed_sensor_MS4525DO

No idea why a merge was necessary