grafx - Extensible Java Graphics Package Code

Changing some dimensions in SmallCanvasConstantOverrides; it looks much better
now.

In NextBlockDisplay, if the block image is too small for allocated canvas
space, chopping area from the top of image instead of from bottom. This fits
better with game layout, e.g. GameSidebar.

In GameSidebar making some slight adjustments to text layout. Explicitly
defining local parameter 'xOffset' which is now set to zero, which determines
the x starting position of text. Text which wasn't left justified with the
next block display didn't look very good. Changing the indentation level of
descriptive text (not title text) to three characters; it was at two
previously.

Adding class net.blockout.production.SmallCanvasConstantOverrides. Still need
to fine tune this.

Renaming performBlockoutConstantOverrides() to
performTetrisConstantOverrides() in class TetrisConstantOverrides.

GameSidebar now uses a smaller font if the canvas size is too small for the
larger font.

Adding a TODO.txt item, having to do with 640x360 resolution.

Made some computer player tests and decided that the strategy
QBEST_STRAT_WEIGHTED_2_BEST_FUTURE_SCORES is better than
QBEST_STRAT_OPTIMAL_FUTURE_SCORE especially for extremely difficult levels,
therefore sticking with that strategy.

Incentivizing an empty well eval score, by bypassing the next eval after that.

Removing TODO.txt comment related to giving bonus eval score for three or more
layers cleared, because that's already implemented.