Fix training script positions altered by variable land dimension change. issue #453

Fix 440, used 'grave' rather than '`' in default binds

darken and contrast the gray images to distinguish more easily from pink

Arbitrarily tweaked to not firepunch loose, and to increase chance of bazooka doing it to about 20%

Improve TestSniperRifle a bit

Allow cleavers to be knocked loose by explosions. Probabilities might need tweaking.

boo, koda