I am marking this task as finished now. Even though not all interfaces have been added, the only classes that don't have a full interface yet are the Renderable classes and I am working on those myself so I will add the interfaces myself as well.
@F0: Remember that the Window class in C++ will be quite different than the one in Ruby. e.g. The CursorX class won't exist. It will be controlled over the Window class and it will be just a Sprite instance.