Arm and disarm with gestures only: left stick right/down for arming, left/down for disarming.
Remove arming switch as it complicates arming gestures logic.
Remove MAV_CTRL_SCALE parameter as it complicates arming gestures logic, advise to decrease TILT_MAX when controlling with a smartphone.
Put some minimal thrust to motors to indicate armed state.
Rename build article to usage article, add flight instructions.
