node-ffi binding does not include methods they are not defined inside a class

[JumpLink]

This is a similar bug as #9 but not related to swig.

[eddyb]

Will take a look. It's possible I overlooked them in the first place because the radare2 bindings don't have any of those global/namespace-level functions .

[radare]

Not sure if we want to maintain the ffi bindings, as long as node changed so much, and emscripten is probably a better option to run C code from Node.

And if we want to call native code maybe is better to use NaN and build the nan boilerplate from Valabind instead of doing all the logic in js which implies a runtime payload