updated to work with libpifacedigital

[h0ru5]

addressing #11

[rc1]

Hey, I just tried this and it works. Thanks. It's running on a Raspberry Pi 2 with node v0.12.5.

To get it to compile I had to preform a couple of steps first. Perhaps this is because I missed something before trying to install (good to know if you had any thoughts on why I had to do this)

1. I cloned libpifacedigital, ran make and make install
2. I cloned libmcp23s17, ran make, then copied mcp23s17.h to /usr/local/include/libmcp23s17/ and copied libmcp23s17.a to usr/local/lib/
3. In my node project I ran: npm install git://github.com/h0ru5/piface-node#566ae2810ebe9db0e68795616e85608697851092 --save-optional

And it worked. Before steps 1 & 2 it wouldn't compile.

[h0ru5]

@rc1, right. i pushed a patch to add a make install to libpifacedigital, but we'll also need one for libmcp23s17

[ArgTang]

+1 for this pull request