Voronoi gridding or other automated grid construction technique.

[tbenthompson]

This is a fun task and would make imprint substantially easier to use in certain cases.

It seems useful to be able to specify a set of simulation points and then ask imprint to deal with constructing tiles itself. In order to do this, we need to be able to construct radii from theta in create_grid. The optimal solution to this problem might be quite difficult to construct since the cost of CSE will varying depending on the direction. But to a first approximation, we want to cover the whole space while minimizing the distance from the edges of tiles to the simulation points.

A dirty approximation to this would be:

• construct a Voronoi diagram from the point set.
• for each Voronoi volume, compute a bounding box and use that box to compute radii.