MAVLink headers generator for Arduino.

Hi!
I use the MAVLink library on an Arduino Due board. However, I can't use the generator for C code directly because the Arduino IDE doesn't let me include subfolders. I mean, if the library is called MAVLink, the mavlink.h file has to be present in the parent folder.

I've only found this link (http://www.qgroundcontrol.org/dev/mavlink_arduino_integration_tutorial) in the qgroundcontrol website and the MAVLink version for Arduino in it is old. Besides, a lot of people use Arduino boards, so I think it would be interesting to fix this.

I've come up with this solution. The mavgen_arduino.py file is a copy of the mavgen_c.py file, but it also creates a folder called MAVLinkArduino which has a MAVLinkArduino.h file which includes the mavlink.h header. So, now I can use MAVLink in my Arduino sketches by including MAVLinkArduino.h.