Merge: lib/geometry: intro more services on points and for angles

Some useful services for games and other geometry heavy applications.

I must say that I'm getting tired of the points API. Dealing with both the numeric complexity and the 2/3D is unpleasant. I will probably remove/separate the 3D part in the near future.

Pull-Request: #1557
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>