grafx - Extensible Java Graphics Package Code

Continuing with comments in EvalFunction w.r.t. "no child left behind"
strategy. This metric may or may not work in the first place. I need to think
about it.

Adding comment describing how we can possibly improve the
noChildLeftBehindMetric().

Writing noChildLeftBehindMetric(). A family of Mexicans was sitting next to me
at the restaurant when I wrote this, when I had the idea for this metric.
Maybe this was a gift from them.

In ComputerPlayer and in LocalBlockoutBoard, making use of new isEmpty() call
which is now part of BlockoutEventQueue.

Implemented a much improved BlockoutEventQueue which uses a circular array
instead of java.util.Vector. It's way more efficient now (not that it was a
bottleneck for performance).

Adding data/level17-computer.blo. Was a good demonstration.

Now waiting for all user movement events to finish before dropping block.

Making use of the caching strategy for next block orientations. In testing
this barely had an effect on performance.

Starting to optimize getNBestMoves(). Not calling into the optimized version,
yet.

Tidying up some loose ends:
- In BlockPlacementStrategy choosing one of the rotations at random.
- In BlockGenerator adding some main() code which prints out information on
unique orientations of an input block.