Code cleanup and minor fixes to Level 3

Levels/Interactables/Coin.gd

@@ -0,0 +1,10 @@
+extends Area2D
+
+signal coin_grabbed
+
+
+func _on_Node2D_body_entered(body: Node) -> void:
+    if body.get_name() == 'Player':
+        emit_signal("coin_grabbed")
+        print("coin!")
+        queue_free()