grafx - Extensible Java Graphics Package Code

Changed section inside commented out block, related to testing 2x2x9 pit.

Adding long comment following coveredHoleMetric(), which explain deficiencies
in covered hole metric and explains the difficulty of computing a maximally bad
score. Also adjusting computed value averageEdgesCornersHoleFactor, making it
more accurate especially for small footprint wells such as 2x2.

Making level 23 really really freaking hard.

Making minor tweaks to the weights on the metric functions. Plays very well.

Cleaning up the comments a bit in coveredHoleMetric(). I was not able to come
up with a more intelligent upper bound on the worst score.

Adding some comments.

Caching the sqrtEdgesCornersWeight() factors on <x,y> grid.

Adding comments describing exactness of worst score computation for nook and
cranny metrics.

Backing out the corner/edge logic in "plug the hole" metric. It did not have a
desirable effect.

Modifying "plug the hole" metric, making holes near corners more disagreeable.