Adds support for Arduino Due and Teensy 3.0 boards

Tested with BreakoutJS client. No issues encountered. All firmata features appear to work for Due and Teensy 3.0 (including Servo and I2C).

To use Due, you need Arduino version 1.5.2 or greater and you need to copy Firmata to:

```/hardware/arduino/avr/libraries/```
and
```/hardware/arduino/sam/libraries```

To use Teensy 3.0 you'll need a fresh install of Arduino 1.0.3 or Arduino 1.0.4 (Arduino 1.0.5 is not yet supported) and install the [teensyduino](http://www.pjrc.com/teensy/teensyduino.html) application. After installing teensyduino, replace the existing Firmata library with this one.