Fixes 889 possible dupe bug

Adds a hotfix to prevent duping with portable cells.
Should possibly fix the NPE crash with switching slots on laggy servers.

src/main/java/appeng/items/tools/powered/ToolPortableCell.java

@@ -186,6 +186,6 @@ public class ToolPortableCell extends AEBasePoweredItem implements IStorageCell,
 	@Override
 	public IGuiItemObject getGuiObject( ItemStack is, World w, int x, int y, int z )
 	{
-		return new PortableCellViewer( is );
+		return new PortableCellViewer( is, x );
 	}
 }