grafx - Extensible Java Graphics Package Code

Adding support for Tetris-style inversions in the event handling code.

Adding launch-tetris.sh.

Adding TetrisInputTranslator and TetrisModeAction, but there is a problem with
inversions. Difficult to explain but a point inversion/reflection isn't what
we want.

Now using BlockModifier in TetrisTest. It is working.

Adding 'checkBlockExtents' to Level and to NightmareModeLevel.

Modifying NightmareModeAction constructor which now accepts BlockModifier
object which may be null.

Adding BlockModifier.

Adding LaunchTetrisTest and TetrisTest. While these do compile and don't
break the build, they are far from finished and most definitely won't work as
intended at this point.

In BlockGenerator, changing rotateX(Block) from 'private' to 'public' access,
for Tetris.

Resurrecting TetrisConstantOverrides and TetrisWellColors.