Add methods to control number of arrows on player.  Adds BUKKIT-3721
Currently Bukkit does not support editing the number of arrows that can be stuck in a player at any given time. This commit changes that by allowing plugin developers to modify the number of arrows to be visually stuck in a player.
Merge branch 'AddArrows' of https://github.com/Turt2Live-DEV/Bukkit into AddArrows

Conflicts:
	src/main/java/org/bukkit/entity/Player.java