Fixes #675 No disabled feature should log spam or crash anymore.

Deprecates the old usage of the AEItemDefinitions via the direct method access of

* blocks()
* parts()
* items()
* materials()

and thus use the new re-direct via definitions().

All definitions are now initialized, no matter what. But SubItems, Items and Blocks are not registered, if by chance are disabled.

src/api/java/appeng/api/definitions/IItemDefinition.java

@@ -0,0 +1,21 @@
+package appeng.api.definitions;
+
+
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+
+import com.google.common.base.Optional;
+
+
+public interface IItemDefinition extends IComparableDefinition
+{
+	/**
+	 * @return the {@link Item} Implementation if applicable
+	 */
+	Optional<Item> maybeItem();
+
+	/**
+	 * @return an {@link ItemStack} with specified quantity of this item.
+	 */
+	Optional<ItemStack> maybeStack(int stackSize);
+}