While libraries are sometimes licensed under LGPL, or even less
restrictive licenses, in this particular case it doesn't really
make sense to encourage direct copying. The problem is that
competing libraries would conflict with each other. It's better
to feed improvements back into a single project.
Though, it's of course possible to fork this project. You can change
the internal classes - for instance, improving or changing the hook
points - without worriying about the public API.
Kristian S. Stangeland