Replaced all instances of Guava's Optional type with Java 8's Optional type, as discussed in #81. (#90)

src/main/java/appeng/facade/FacadeContainer.java

@@ -20,6 +20,7 @@ package appeng.facade;
 
 
 import java.io.IOException;
+import java.util.Optional;
 
 import io.netty.buffer.ByteBuf;
 
@@ -149,9 +150,9 @@ public class FacadeContainer implements IFacadeContainer
 				}
 				else if( !isBC )
 				{
-					for( final Item facadeItem : AEApi.instance().definitions().items().facade().maybeItem().asSet() )
-					{
-						final ItemFacade ifa = (ItemFacade) facadeItem;
+					Optional<Item> maybeFacadeItem = AEApi.instance().definitions().items().facade().maybeItem();
+					if (maybeFacadeItem.isPresent()) {
+						final ItemFacade ifa = (ItemFacade) maybeFacadeItem.get();
 						final ItemStack facade = ifa.createFromIDs( ids );
 						if( facade != null )
 						{