Add unique IDs to tasks
Added missing ARMOR_STAND EntityType.

* Fixed wrong return values in Enderman.
Fixed wrong return type in Wither.
Fixed derp with Wither javadoc.
Added BiomeTypes.
Merge pull request #271 from SpongePowered/feature/biomes

Added BiomeTypes.
Fix wrong spelling.
Add method to get running time in ticks
Clarify running tick time javadoc
Add World Border API
Remove most static methods and unify 'valueOf'/'values' functions on GameRegistry