Multi-world fixes.
Boards are deferred properly if on an unloaded world
World unloading is now handled - boards are unregistered correctly
Version => 1.0.2
Play piece_captured effect slightly above the board
Makes e.g. explosion effects more visible
Use dhutils-lib 2.6.0-SNAPSHOT (MC 1.6 compat)
Version => 1.0.3
Merge branch 'master' of github.com:desht/checkers

Conflicts:
	pom.xml