Added safe to use Serial Port Plugin for Arduino

Finally. It's here :)

To use - there is a ArduinoPluginActor you can pull into a blueprint.

3 calls : Connect(comPort), SetSpeed(fan1, fan2), Disconnect()

Important notes:
All fan speeds MUST be 0-9 only.

All methods will never throw errors - also won't tell you if something worked, can change to return bools?
Connect() - when given a correct comport sleeps a thread for 2 seconds, giving the arduino time to reset.
With a wrong com port (unable to open/write to it), returns immediately.

Every call to connect MUST be followed sometime by a call to Disconnect() on the same actor - else the serial port handle does not close !!! and will not close until process exits. So if you spawn an actor and connect it, it's holding the comport, any other actors you spawn will never be able to get the handle.