First major refactoring of world package.

Moved the region stuff back into the region file, replacing its entire
contents.  Moved other stuff into the utils file, replacing its entire
contents.  Wrote tests for the utils stuff.
Rearranged code locations in files, and added tests.

Lots of minor changes and reorganizations.  Need more tests.
Can now skip the long test when using -short argument.

The test currently takes approximately one minute, which is pretty
long!  If I can increase test coverage elsewhere, this can be saved
for integration testing.
Major increase of test coverage for world package.

The price, of course, is runtime.  The major culprit appears to be
writing regions.  Once this is resolved, things should go much
quicker!  Right now, though, 73% coverage for thirty seconds is a good
deal.