Fork https://github.com/ArduCAM/Arduino

[r4dx]

Justification: This library uses digitalWrite static method, the idea is to pass special PinWriter interface and implement PinWriter for MCP23017. For simplicity reasons SPI part should be wired directly to ESP8266.

Definition of Done:

1. Fork in github
2. Create separate project in VS
3. Choose the method to modify sources in the main project without too much effort (git submodule?)

[r4dx]

Decided to just create symbolic link for it in lib/ - much easier and do the job as good.