autotest: fixed rover mission completion
Revert "RC_Channel: removed pwm_out variable from RC_Channel"

This reverts commit 8e4a003d8dca3ee1bc3ae301d96c3cce53af40cf.

It is used by MotorsMatrix
Rover: minor parameter documentation updates
Plane: added HIL_SERVOS option

this allows for real servo output in HIL
Merge remote-tracking branch 'upstream/master'