grafx - Extensible Java Graphics Package Code

Getting rid of IllegalStateException usage in BlockGenerator. Making things
consistent.

Fixing some Javadoc issues and marking an unused function as 'private' in
BlockGenerator. Just wrapping up with this class. Nearing completion.

Making a few minor optimizations and documentation changes.

Making an optimization to equalsModuloOrientation().

Marking two more functions that are not being used externally as 'private', in
BlockGenerator.

Tidying up some functions that aren't being used anywhere.

Modifying comment above putUniqueOrientedBlock().

Making six of the rotate functions in BlockGenerator 'private' because they are
not being used anywhere; don't want to clutter the Javadoc.

Optimizing BlockGenerator.equalsWithOrientation().

Adjusting comment on BlockGenerator.getCenterOfMassDirect().