grafx - Extensible Java Graphics Package Code

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.

Fixing spelling error in comment in ffmpeg-overlay.sh.

Implementing short circuit method for end of level, for qBestStrategy other
than QBEST_STRAT_OPTIMAL_FUTURE_SCORE.

Fixing a bug where end of game was not being seen one move ahead of time,
because the wrong layersToClear value was being passed to evalWithNextBlock().
qSearchBreadth is being reverted to 24, since the recent change to 32 had
nothing to do with fixing this problem. Also adding a TODO.txt item related to
picking low-hanging fruit related to the situation where a pit/well is cleared
of all cruft, which usually results in a bonus points situation.