Added comment about IMU orientation
Keep calculating angle when quadcopter is disarmed
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IMU was reorientated
Added elevator and aileron control
Make sure that throttle is applied

This is just to be extra sure and will most likely be removed later on
Smmoth acc z-axis before using it

Source: https://github.com/cleanflight/cleanflight
Tuned PID controller

Almost hovering
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