Efficiently rendering time-varying trimeshes

A frequent use case for trimesh rendering is to plot a time-varying mesh where the mesh coordinates are static but the node or triangle values vary over time. Using the current approach the canvas.trimesh has to recompute the intermediate datastructure each time which is very inefficient when you are trying to plot hundreds or even thousands of different timesteps of the same mesh. We either need to rethink the intermediate datastructure or we should find a way to efficiently update the mesh datastructure with the time-varying values.