grafx - Extensible Java Graphics Package Code

Adding a little bit of a Javadoc comment to BlockPlacementStrategy.

Removing unused import statement for HalfPosition.

Making massive changes to BlockPlacementStrategy, finally. Still need to do a
major proofread, esp. in function getNBestMovesFin(). Major changes on
priority of post drop slide moves.

In net.blockout.meta.BlockGenerator, making getBlockName(Layer[]) public since
that does not depend on center of block rotation. Also adding a new function,
getBestCanonicalRotation(), and adding necessary code to support it.

Very minor changes, mostly comments in code. Taking out an unnecessary
inequality check.

This is part of an incremental change, which is redoing getNBestMoves() in
BlockPlacementStrategy. This is a semi-stopping point, I want to save the work
in case I need to roll back. The game seems to work fine in this state, but
the changes are unfinished. Need to go over the code with a fine-toothed comb
still, at the very least.

Changing order of loops in BlockPlacementStrategy again. We're going for
performance AND accuracy.

Moving location of another loop in BlockPlacementStrategy, in order to prevent
excessive computations.

In BlockPlacementStrategy paving way for further optimizations, w.r.t. loop
order.

Fixing all Javadoc warnings.