The kgs-genmove_cleanup command now causes Orego to bias searching (by adding priors to) moves adjacent to dead enemy stones in an attempt to kill them.

Also, there are tests in MctsPlayerTest that test this behavior in a few hand-made problems.
Increased biasing of cleanup moves, and removed needless stderr output.
Merge branch 'master' into fix_kgs-genmove_cleanup
Added comment to NeighborCounts giving credit to Lukasz Lew.
Trivial cleanup of Board.
Board.setUpProblem no longer plays an extra pass to change the color to play.
Removed unused imports from BoardTest.
Merge branch 'master' into clean