Update mega2560.json w/more info

added more info, by the fields found in leonardo.json
Adds some communication and networking libraries
added TinyLily support
uno.json

USB vid & pid from my board (UNO R3)
added megaADK, more vid&pids (#7)

added data about megaADK from
http://arduino.cc/en/Main/ArduinoBoardMegaADK
vid's and pid's from http://www.linux-usb.org/usb.ids