UI testing env and working text buttons

Former-commit-id: b8fd27c7f71f9bc8da259ae132badcbc9ce117ac

src/net/torvald/terrarum/gameactors/HumanoidNPC.kt

@@ -52,6 +52,7 @@ open class HumanoidNPC(
             set(value) {
                 actorValue[AVKey.SCALE] = value
             }
+        override var category = "npc"
 
         override fun secondaryUse(gc: GameContainer, delta: Int) {
             // TODO place this Actor to the world