Minecraft wiki entry for Development_versions, associated text: MC-236 – Half slab and pistons graphical glitch.
Fixed mobs glitching through wooden floors.
Fixed players glitching through beacons.
Fixed redstone repeaters getting stuck in 'on' state.
Fixed a number of minor font issues.
Fixed wet wolves looking way too scary.
Fixed a bug that allowed any item to be placed in the armor slots.
Fixed monster spawners spawning mobs too quickly.
Fixed invisible falling sand entities.