Smoothing

First mesh operator I implemented was the most intricate one, catmull clark mesh smoothing. Also added some management code to build meshes and added a cube "generator". These upgrades added ~1.2kbytes to the engine which is now at 5488 bytes - however the old butterfly mesh smoothing scheme we used would have added twice as much without even mentioning all the mesh topology issues we always had with it. The 12kbyte engine size might still be possible if all goes well.