Minecraft wiki entry for Redstone_Update, associated text: Better lighting
Tools enchanted with Efficiency only speed up the mining speed of the intended blocks for that tool
New inventory management features
More specific death messages
Increased range of beacon effects
Brewing stands, chests, detector rails, dispensers, and jukeboxes now emit a redstone signal when a redstone comparator is placed against them.
Nether brick is now craftable
Changed the shooting mechanics of skeletons
The spawn rate of slimes in swamps now depends on the moon phase