Taken from Bukkit's Material class, with credits.
Allows to know types and properties of blocks.
+ Use database for "is solid" checks
+ Add "can harm players" method
+ Faster movements, falling seems natural now
+ Shorter error message when ping failed
- World is now properly parsed and stored from chunk data
- Block changes are also handled and world updated accordingly
- Added ground checking, the player will move down to reach the ground
- Performance tweaking in Protocol18, using lists instead of arrays
- Fix player look not properly skipped causing invalid location after
teleport