Playing around the edge of the envelope

I was wrong about hitting hardware limits yesterday. I figured out how
to run the JVM with heap size increased to 1GB from the default 64MB.
OptimalPlayer was able to find non-trivial (previously unknown)
solutions in a couple games with up to four moves. Beyond that, I still
run out of heap space (my machine has only 2GB of RAM). I played around
somewhat with forced garbage collection, but that isn't helping. Will
have to look at an algorithm that trades time for space.