Major Refactoring of Bootstrap Code (#75)

- Refactored boostrap code:
  * Completely reworked item/block/tile registration.
  * Fixed server side startup.
  * Fixed server side startup.
  * More documentation.
  * More heavy cleanup
  * More cleanups.
  * Major refactoring of state mapping and fixes a lot of other issue related to item rendering.
  * Fixes sky chest item models (no item TESR).
  * Only use CachingRotatingBakedModel for tile entities automatically.
  Fix default rotation of quartz pillar for item model.
  * Used method reference instead of lambda for ItemMeshDefinition for multiparts.
  * Removed unnecessary IHasSpecialItemModel
  * Removed unused IconReg class.
  * Updated resource pack version.

src/main/java/appeng/items/parts/ItemMultipartRendering.java

@@ -0,0 +1,33 @@
+package appeng.items.parts;
+
+
+import net.minecraft.client.renderer.block.model.ModelResourceLocation;
+import net.minecraft.item.ItemStack;
+
+import appeng.bootstrap.IItemRendering;
+import appeng.bootstrap.ItemRenderingCustomizer;
+
+
+public class ItemMultipartRendering extends ItemRenderingCustomizer
+{
+
+	private final ItemMultiPart item;
+
+	public ItemMultipartRendering( ItemMultiPart item )
+	{
+		this.item = item;
+	}
+
+	@Override
+	public void customize( IItemRendering rendering )
+	{
+		rendering.meshDefinition( this::getItemMeshDefinition );
+	}
+
+	private ModelResourceLocation getItemMeshDefinition( ItemStack is )
+	{
+		// TODO: Avoid object creation here. This happens every frame
+		return new ModelResourceLocation( item.getTypeByStack( is ).getModel(), null );
+	}
+
+}