Java Edition 13w37a

13w37a is the third snapshot released for 1.7.2.

Additions

 * Added to place blocks without the use of FallingSand
 * Syntax:
 * Valid values for oldBlockHandling: "replace" to place the specified block (throws error message if the same block exists already), "keep" will only place blocks in air, and "destroy" will mine the existing block and drop an item before placing the new block
 * Added to check for blocks in specific locations
 * Syntax:
 * All blocks beyond X/Z 30 million (±30,000,000) from origin now act as solid blocks, and cannot be targeted with the crosshair.
 * This includes air blocks.
 * This creates essentially an invisible wall which extends infinitely, even above and below the chunks.
 * As all blocks function as solid, if the player is moved outside the boundary via external tools, they will be unable to move outside the block space they are within.
 * Despite the above, the camera can still move normally. This reveals that ghost chunks still generate, as the camera can pass through normally solid blocks beyond the boundary.

Changes

 * Slightly changed Mesa biome generation to appear more layered
 * Improved command blocks.
 * Increased the character limit to "many thousand characters"
 * Improved Nether portals.
 * Planned to have odd width to allow for design variations
 * Can be built large enough so that Ghasts can enter the Overworld.
 * Portals can now be activated from any block within the portal, not just the bottom (when any fire block appears inside the frame)
 * New nether portal building rules: Any size from 4x5 to 23x23, but rectangular
 * Block/item IDs can now be referred to with names instead of IDs
 * Improved
 * Will now print renamed items' name in chat and show tooltips when hovered over
 * Improved the chat system
 * "Useful to map makers, modders, players and server admins"
 * Added a way to do things when clicking things in chat, like executing a command
 * Other actions include opening a URL and showing an item tooltip when hovered on
 * "Saved screenshot as" messages can now be clicked to open the screenshot, takes you to the .minecraft folder
 * Names can now be clicked to PM people
 * Added to send chat messages with custom functionality to players - sender will not appear
 * Syntax example:
 * Removed the item forms of many blocks: bed (26), piston head and extension (34 & 36), redstone wire (55), wheat crops (59), standing and wall sign (63 & 68), wooden and iron door (64 & 71), lit redstone ore (74), unlit redstone torch (75), sugar cane (83), cake (92), unpowered and powered repeater (93 & 94), pumpkin and melon stem (104 & 105), nether wart (115), brewing stand (117), cauldron (118), lit redstone lamp (124), tripwire (132), flower pot (140), skull (144), and unpowered and powered comparator (149 & 150). They can no longer be obtained with, but can be created with.
 * Also The Locked chest's item form was removed.
 * Lava source blocks can no longer be destroyed by explosions

Fixes
15 bugs fixed

From released versions before 1.7.2
 * – Zombie Pigman from Nether Portal still spawns even if  is false
 * – Adjacent Obsidian Blocks prevent Nether portal appearing
 * – Breeding animals gives xp even if  gamerule is false
 * – Horse Breeding Doesn't Produce Markings Correctly on Foal
 * – Shearing sound does not play when shearing a mooshroom
 * – Flowing lava can be blown up by TNT

From the 1.7.2 snapshots
 * – Water and Ice no longer transparent on fast graphics
 * – Minecraft crash near 30 million blocks
 * – Some plants not working properly with flowerpots
 * – All the new flowers give only 1 of their respective dye whereas dandelions and 'roses' (now poppies) still give 2
 * – Thorns enchantment backfires
 * – Flint and steel sound and hand animation do not play when igniting a creeper

From the previous snapshot
 * – Statistics and Achievements un-pause the game
 * – Ender cystals in the overworld cause non-reasonable amount of lag
 * – Sugar Cane with no water