Arm/disarm and SAS modes order safety fixes

I had a crash because disarmed in flight in altitude hold mode (throttle = 0 means just decending with constant speed). I fixed current state machine to allow arming/disarming only in manual SAS mode.

Throttle threshold reduced from 0.2 to 0.1 because Hyon reported that for very light copter with hovering throttle ~0.3 unwanted disarms also happens.

Order of SAS modes changed: manual mode is not in the middle now. In emergency situation pilot should be able to switch to manual mode easy.