Optional renaming of methods according to Scala naming conventions

Currently bindgen outputs methods with the same names as in native library.
It would be good to have a way to transform names according to Scala naming conventions
```scala
// before
def my_function(arg: native.CInt): native.CInt = native.extern

// after
@name("my_function")
def myFunction(arg: native.CInt): native.CInt = native.extern
```