visit and draw improved.

`visit()` and `draw()` are improved.
they both receive:
 - `Renderer`
 - `kmMat4` for transformation
 - `bool` whether or not the transform changed from the previous frame

Although `draw` and `visit` are not using the 3 new parameters,
they will start using it in the coming days (or weeks, or months).

Those parameters are needed for:
 - `Renderer` shouldn't be a singleton. There should be one renderer per Director. There could be more than one renderer
 - we should get rid of `kmGLXXX` functions since nodoby knows what is happening. the `kmMat4` is for that.
 - whenever possible, we should try to optimize the multiplications. the `dirty` flag is for that.

We need those changes, so, it is better to change the API now, and not right after v3.0-final is released.