fixed issue with elevator fluctuations at low airspeed in pitch controller

AttPosEKF dead reckoning fix

this can be used to override the board type check. Useful when
changing bootloaders

Servo gimbal

Made aux output pwm rate, min, max, disarmed and failsafe values configurable the same way as for the main outputs

Renamed existing build system to be more verbose

Added start of the gimbal driver for SK450

Fixed float equality checks

added quaternion rotation method test

mkblctrl: cmd switch for min_rc and max_rc

From original

Add RC_CHAN_CNT, RC_TH_USER for QGC

These are used by ground station software