Initial logging additions.

Rudimentary logging to get things set up for later, which should use
extremely verbose and rich logging to journal world generation progress.
Remove irrelevant comments.

These comments have been hanging around from when I copied this code
from the matplotlib contour plot demo. No longer relevant to the
function they're in.
Add tests.things module. Add tests.things.IntMap.

things will be a place for experimental/testing structures to live.

IntMap is a Map that only contains integer values. This is for testing
to find out if floating point values are causing issues with plotting
large maps.