add RPi support

hi,
![node-ftdi-install](https://cloud.githubusercontent.com/assets/7436938/3142483/f5b98f54-e9c0-11e3-896a-83fcd29a60d6.PNG)


I add the support for Raspberry Pi.
Additional i removed the verbose argument at tar command for clarity
Also i add the verbose argument at cp and ln in order to see what happen