Fixed bug where falling blocks were not tracked

Fixes #2130
Fixed bug where Berserk deletes items
when the players inventory is full.

Fixes #1947
Add option to control Unarmed item pickup behavior

By default when using Unarmed, picking up items is prevented when a
players entire inventory is full, except for his empty hand.
Fixed broken isWaterBottle() check
Add Snow to Excavation guide
Added SkillAPI used to get a list of skill names

This prevents having to rely on the SkillType enum
Actually fix the isWaterBottle() check

Fixes #2134

For some reason Bukkit wanted to use Potion(PotionType type, int level)
when calling .toPotion(), even though .getDataValue() is 0.
Prepare for UUID update
Add u.uuid here
Deprecate methods in ExperienceAPI
UUID Conversion stuff
Deprecate PlayerProfiles relying on names
Add hidden options for uuid conversion
UUID flatfile stuff
Save and load profiles using UUIDs
fall back on usernames if neccesary
Update playername in database when a name changes
Load UUID with SQL