Crouching monkey, hidden mousetrap

Monkeys will no longer move randomly while being pulled.

Added "hide" verb to mousetraps, placing them on the same layer as hidden mice.

Triggered mousetraps and dead mice will be moved back to the top layer.

Changelog updated accordingly.

Two config variables added - disable_player_mice and uneducated_mice. The first, if enabled, prevents players from spawning as mice, and the second, if enabled, prevents mice from understanding human speech (which they now do my default)

universal_understand = 1 now allows player-controlled mobs to understand what everybody is saying without necessarily allowing them to talk back intelligibly. Mice have universal_understand = 1 by default.