Оптический датчик положения для APM

Description:
- To improve the precision when you can't use GPS, APM: Copter now support optical Flow V1.0 based on mouse sensor

Probelms:
- Sensor can only work under good lighting condition
- Using fixed foucus lens, so it cannot focus lens of objects that within 30cm
- Rotate sensor will make sensor in disorder

Connecting sensor to APM2.5, APM2.52, APM2.6, APM2.8 all can be used
- Connecting with VCC, GND, MISO, MOSI, SCLK, and NCS pins
- Default installation mode is the camera heads down, the pins heads forward
- Disconnect with MISOLVL jumping cable on the back of the board, rewelding the MISO pins at 3.3V voltage. In this way, it won't inteference MPU6000