- added new pfio.c native methods using ffi
 - updated ffi to ~> v1.7.dev
 - implemented Piface.read_input and Piface.read_output
 - changed all piface code references to lowercase (excluding the primary module)
 - changed gem name to lowercase
 - added Piface::HIGH and Piface::LOW
 - updated README.md
 - added ffi_lib path fallbacks
Merge branch 'master' of https://github.com/blakejakopovic/piface