modularised inventory cell behaviour

src/net/torvald/terrarum/ui/UIItem.kt

@@ -193,8 +193,6 @@ abstract class UIItem(var parentUI: UICanvas, val initialX: Int, val initialY: I
         return false
     }
     open fun touchDown(screenX: Int, screenY: Int, pointer: Int, button: Int): Boolean {
-        println("uiitem ${this.javaClass.name} touchdown")
-
         var actionDone = false
 
         if (parentUI.isVisible) {