grafx - Extensible Java Graphics Package Code

Upping the number of layers to clear on level 26, by one layer.

Moving code around in BlockoutConstants to make it easier to modify quickly.

Adding a new level 21, pushing levels 22 through 29 to now be levels 23 through
30. Level 21 is a 4x3 pit with reasonable blocks, good for demo.

In LevelTest and in NightmareLevelTest, now using external class StatsUpdater
instead of relying on duplicated code.

In LaunchNightmareLevelTest, the introductory audio (as part of
DaemonAudioAndAWT.createAudioAndAWTThreadsAsDaemon()) has been changed from
"woohoo.au" to "speedup.au" to be in line with other start/spash screens. The
"woohoo.au" is very loud, and isn't suitable as an introduction.

Removing fully qualified constructor with statement
'new net.blockout.event.encode.SynchronizedModeGameRecorder()' (removing
package name because that class is being imported).

Removing System.out.println() statement, which printed something like:
"best anticipated eval score: XX.XXXXXX".

Making some changes to some of the hard levels:
- In level 21 (the hard 5x2 pit) adding the twofer block, weight 1. This
makes the level slightly easier and definitely more predictable for
solving by computer player.
- In level 23 (the hard 4x4 pit) reducing weight of all blocks from 2 to 1.
This makes the play a little bit more predicatble; the computer player
seems to pass the level on a more regular basis, even though it was very
rare that the computer player didn't pass this level.
- In level 24 (the hard 3x3 pit) excluding the unit cube from set of blocks.
This makes the level harder. Surprisingly the computer player seems to
have no problems passing even the harder version, now.

Now using external class StatsUpdater in ComputerPlayerTest.

Removing two unused import statements from LevelPlayback.