AP_AHRS: fixed wind reporting with EKF and no airspeed sensor

the EKF does not estimate wind without an airspeed sensor
Plane: fixed a bug in PWM based throttle failsafe

many thanks to Sam Tabor for finding this bug!
Plane: prepare for release of 3.0.1
AP_GPS: fixed a build warning

Debug() should not be exposed in public headers
DataFlash: added separate logging of each GPS
Plane: ensure we log both GPS at the time we receive a msg
Copter: ensure we log both GPS at the time we receive a message
Rover: ensure we log both GPS at the time we receive a message
AP_TECS: Parameter TECS_LAND_SPDWGT allows custom landing speed weight.