made Turtle a static class

src/lib/turtle/TurtleExecuter.hx

@@ -71,25 +71,25 @@ class TurtleExecuter {
 	private function executeInst(instruction:TurtleInstruction):Outcome<Noise, String> {
 		switch instruction {
 			case Forward:
-				return Turtle.instance.forward();
+				return Turtle.forward();
 			case Back:
-				return Turtle.instance.back();
+				return Turtle.back();
 			case Up:
-				return Turtle.instance.up();
+				return Turtle.up();
 			case Down:
-				return Turtle.instance.down();
+				return Turtle.down();
 			case TurnLeft:
-				return Turtle.instance.turnLeft();
+				return Turtle.turnLeft();
 			case TurnRight:
-				return Turtle.instance.turnRight();
+				return Turtle.turnRight();
 			case Dig(dir):
-				return Turtle.instance.dig(dir);
+				return Turtle.dig(dir);
 			case Place(dir):
-				return Turtle.instance.place(dir);
+				return Turtle.place(dir);
 			case PlacseSign(dir, text):
-				return Turtle.instance.placeSign(dir, text);
+				return Turtle.placeSign(dir, text);
 			case Select(slot):
-				var r = Turtle.instance.selectSlot(slot);
+				var r = Turtle.selectSlot(slot);
 				if (r.isSuccess()) {
 					return Outcome.Success(null);
 				} else {

src/lib/turtle/TurtleExt.hx

@@ -37,9 +37,9 @@ class TurtleExt {
 		var ret:Int = 0;
 
 		for (i in 0...Turtle.MAX_SLOTS) {
-			var slotItem = Turtle.instance.getItemDetail(i).orNull();
+			var slotItem = Turtle.getItemDetail(i).orNull();
 			if (slotItem != null && slotItem.name == item) {
-				ret += Turtle.instance.getItemSpace(i);
+				ret += Turtle.getItemSpace(i);
 			}
 		}