Add pre compiled binaries for windows, mac and linux

Adds pre compiled binaries for all 3 major platforms using node-pre-gyp. This is the same thing we did and are using in node-serialport, has worked great so far.

@peterbraden after merging I do need your help to generate the secure keys in travis and app-veyor (since they are repo and account bound respectively). We also need to create a new branch for OSX pre-compiled binaries called `osx-binaries`, since travis does not support multiple OS builds, so we need a different branch to compile for OSX.

I'm creating a pre-compiled-binaries.md file to describe the process, I'll also add a make task to make it easier to generate the binaries with each release.

BTW we at (The Hybrid Group)[https://github.com/hybridgroup] are sponsoring the AS3 buckets, we also do it for node-serialport (as mentioned above) and we'll be adding them for (node-gamepad)[https://github.com/creationix/node-gamepad].

Regards,