Consider world created before WorldLoadEvent is called.
Added Eclipse project name override to build script.

Intended to fix weirdness with importing the files generated by the
Eclipse gradle plugin.
Added snow block placement handling.
Added note about Trello to CONTRIBUTING.md.
Refactored out use of JSONObject in the protocol in favor of TextMessage.
Minor cleanup.
Added item FlintAndSteel
added TNT/explosions
Explosion: drop blocks, set them on fire, fire events
use BlockVector
some kind of entity damage (to be finished)
added damage based on rayTracing for entitys in explosions
added TNT block (explosion)
formatting, correct use of EventFactory, constants for explosion power, some javadoc changes
add blocks only if the damage is high enough, don't add air blocks
added ItemTool for easier damage handling; formatting
fixed explosion values
added yield for explosion
some start for ExplosionPacket
use constant Explosion.POWER_TNT instead of value 4