B+ Revision check & Pins

This was my attempt at creating a PR for issue #8. I was not sure what to do with the hackablePins array as I'm not entirely sure what the purpose of that array is. Hope this helps get things up to date for the B+. Changes seem to be working okay with mine when it comes to reading pins, have no started messing with blinking pins.
Seems ok to me, according to the new Raspi B+ GPIO [schema](http://www.raspberrypi.org/wp-content/uploads/2014/04/bplus-gpio.png) & [table](http://elinux.org/RPi_BCM2835_GPIOs)