Fix MaterialData directions being incorrect. Fixes BUKKIT-3160

Prior to 49690f9, BlockFaces were mostly correct in their respective
MaterialData classes. However, a lot of things were not updated since
implementation and broke without being addressed.

This fixes any discrepancies with Block data.

src/main/java/org/bukkit/material/Command.java

@@ -1,6 +1,5 @@
 package org.bukkit.material;
 
-import org.bukkit.block.BlockFace;
 import org.bukkit.Material;
 
 /**