Java Edition 13w18a

13w18a is the fourth snapshot released for 1.6.1.

Additions

 * Added Block of Coal.
 * Crafted with 3x3 coal.
 * Crafted only with coal, not charcoal.
 * Can be used as furnace fuel and smelts 72 items, like 9 coal.
 * Can be used to store large amounts of coal.
 * Start of a new texture loading system.
 * New "missing texture" texture
 * Added crafting recipes for lead and hay block.
 * Hay blocks are crafted with 3x3 wheat.
 * Hay blocks cannot be uncrafted.
 * Added chest generation in Nether Fortresses
 * Chests generate in corners of interior corridors

Changes

 * Tweaked horse equipment obtainability
 * Players can no longer craft horse armor
 * Horses now use the same saddle that pigs use
 * Saddles can now be found in most generated chests
 * Added horse armor to dungeons
 * Removed Horse Saddle
 * Adjustments related to horses makes them more practical later in the game
 * Redstone Comparators now output a signal for Cauldrons and End Portal frames
 * Cauldrons give from zero signal (empty) to three signal strength (full) depending on water inside
 * End Portal frame varies between zero and fifteen signal strength, depending on if an Eye of Ender is present
 * Mechanic whereby zombies spawn more zombies adjusted and is no longer easily visible to the player
 * Zombies spawn in dark areas far from the player or in caves
 * Carpets can now be placed on translucent blocks
 * This includes glowstone, glass, glass panes, and beacons
 * Beacons will still function under carpet

Fixes
8 bugs fixed

From released versions before 1.6.1
 * – Green arrow bug on maps in frames
 * – Mobs not realizing they killed their attacker and trying to attack empty space
 * – Dogs wont stop snarling after punched by someone else
 * – Despawning cured zombie
 * – Lava decay fails to schedule block update
 * – Blocks stop updating one minute after entering the Nether or the End

From the 1.6.1 snapshots
 * – You can pick up command blocks with any pickaxe

From the previous snapshot
 * – Can't place carpet on translucent blocks