implement some of the missing GPIO pin functions
implement some of the missing GPIO pin functions

luetgendorf/Espruino,lancernet/Espruino,luetgendorf/Espruino,lancernet/Espruino,lancernet/Espruino,wilberforce/Espruino,lancernet/Espruino,lancernet/Espruino,wilberforce/Espruino,luetgendorf/Espruino,wilberforce/Espruino,lancernet/Espruino,lancernet/Espruino,luetgendorf/Espruino,wilberforce/Espruino,wilberforce/Espruino,luetgendorf/Espruino,wilberforce/Espruino,luetgendorf/Espruino,luetgendorf/Espruino,wilberforce/Espruino