Pull Contributing Guidelines and Requirements into CONTRIBUTING.md
Add link to CONTRIBUTING.md in README
Add missing new line to README.md
Remove point about squashing commits.
Add an enum for Nether Wart growth stages. Adds BUKKIT-1599
BlockState for Command Blocks. Adds BUKKIT-3805.
Pulling all pending Bukkit-JavaDoc changes
Update Bukkit for Minecraft 1.5.1
Added the hasGravity method to Blocks. Adds BUKKIT-3832
Add Fish (Hook) entity to PlayerFishEvent. Adds BUKKIT-1025
Add method to get the source of a TNTPrimed.  Adds BUKKIT-3815
Add ability to modify ThrownPotion properties. Adds BUKKIT-3197
Map old wildcard recipe data to new 1.5 value. Fixes BUKKIT-3849
Add Dropper BlockState.  Adds BUKKIT-3750
Add InventoryMoveItemEvent. Adds BUKKIT-3765

This event is being called whenever a block or entity (e.g. hopper) tries to
move an item from one inventory to another inventory (one inventory may be
the hopper itself).
Add Thorns to DamageCause - Related to BUKKIT-3505
Add ability to change player item in hand. Adds BUKKIT-3318
Add methods to check for conflicting enchantments. Adds BUKKIT-3830
Allow fishing success rate to be adjustable. Adds BUKKIT-3837