diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..6ef72f83
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.idea/
+*.iml
+
diff --git a/com/stencyl/AssetLoader.hx b/com/stencyl/AssetLoader.hx
index 0fb5dd42..6025a5c6 100644
--- a/com/stencyl/AssetLoader.hx
+++ b/com/stencyl/AssetLoader.hx
@@ -1,9 +1,9 @@
 package com.stencyl;
 
-import haxe.xml.Fast;
+import com.stencyl.models.IdType;
 
 interface AssetLoader
 {
 	function loadResources(resourceMap:Map<String,Dynamic>):Void;
-	function loadScenes(scenesXML:Map<Int,String>):Void;
+	function loadScenes(scenesXML:Map<IdType,String>):Void;
 }
\ No newline at end of file
diff --git a/com/stencyl/Data.hx b/com/stencyl/Data.hx
index 6a307e9c..507c2b3b 100644
--- a/com/stencyl/Data.hx
+++ b/com/stencyl/Data.hx
@@ -9,6 +9,8 @@ import com.stencyl.io.SoundReader;
 import com.stencyl.io.SpriteReader;
 import com.stencyl.io.TilesetReader;
 
+import com.stencyl.models.IdType;
+
 import openfl.Assets;
 import openfl.Lib;
 import haxe.xml.Fast;
@@ -83,7 +85,7 @@ class Data
 	//*-----------------------------------------------
 	
 	//Map of each [sceneID].xml by ID
-	public var scenesXML:Map<Int,String>;
+	public var scenesXML:Map<IdType,String>;
 	
 	//Map of each [sceneID].scn by ID
 	//public var scenesTerrain:Map<Int,Dynamic>;
@@ -151,7 +153,7 @@ class Data
 		
 		updatePreloader(90);
 		
-		scenesXML = new Map<Int,String>();
+		scenesXML = new Map<IdType,String>();
 		
 		loader.loadScenes(scenesXML);
 		
diff --git a/com/stencyl/Engine.hx b/com/stencyl/Engine.hx
index 5dcb132c..cbd94b97 100644
--- a/com/stencyl/Engine.hx
+++ b/com/stencyl/Engine.hx
@@ -15,6 +15,9 @@ import com.stencyl.behavior.BehaviorManager;
 import com.stencyl.behavior.BehaviorInstance;
 import com.stencyl.behavior.Script;
 
+import com.stencyl.models.IdType;
+import com.stencyl.models.IdType.IdUtils;
+
 import openfl.geom.Point;
 import openfl.geom.Rectangle;
 import openfl.display.DisplayObject;
@@ -209,7 +212,7 @@ class Engine
 	
 	private var leave:Transition;
 	private var enter:Transition;
-	private var sceneToEnter:Int;	
+	private var sceneToEnter:IdType;
 	
 	
 	//*-----------------------------------------------
@@ -625,7 +628,7 @@ class Engine
 	}
 	#end
 	
-	public function begin(initSceneID:Int)
+	public function begin(initSceneID:IdType)
 	{
 		loadedAtlases = new Map<Int,Int>();
 		atlasesToLoad = new Map<Int,Int>();
@@ -805,7 +808,7 @@ class Engine
 		loadScene(initSceneID);
 	}	
 	
-	public function loadScene(sceneID:Int)
+	public function loadScene(sceneID:IdType)
 	{
 		collisionPairs = new IntHashTable<Map<Int,Bool>>(32);
 		
@@ -817,7 +820,7 @@ class Engine
 		
 		scene = GameModel.get().scenes.get(sceneID);
 		
-		if(sceneID == -1 || scene == null)
+		if(sceneID == IdUtils.INVALID_ID || scene == null)
 		{
 			scene = GameModel.get().scenes.get(GameModel.get().defaultSceneID);
 			
@@ -1719,7 +1722,7 @@ class Engine
 		world = null;
 	}
 	
-	public function switchScene(sceneID:Int, leave:Transition=null, enter:Transition=null)
+	public function switchScene(sceneID:IdType, leave:Transition=null, enter:Transition=null)
 	{
 		// trace("Request to switch to Scene " + sceneID);
 
diff --git a/com/stencyl/behavior/Script.hx b/com/stencyl/behavior/Script.hx
index 71cc9447..0d4b7479 100644
--- a/com/stencyl/behavior/Script.hx
+++ b/com/stencyl/behavior/Script.hx
@@ -64,6 +64,8 @@ import com.stencyl.event.EventMaster;
 import com.stencyl.event.NativeListener;
 import com.stencyl.io.SpriteReader;
 
+import com.stencyl.models.IdType;
+
 import motion.Actuate;
 import motion.easing.Linear;
 
@@ -1177,7 +1179,7 @@ class Script
 	 *
 	 * @return The ID current scene
 	 */
-	public static function getCurrentScene():Int
+	public static function getCurrentScene():IdType
 	{
 		return getScene().ID;
 	}
@@ -1185,9 +1187,9 @@ class Script
 	/**
 	 * Get the ID of a scene by name.
 	 *
-	 * @return The ID current scene or 0 if it doesn't exist.
+	 * @return The ID current scene or IdUtils.INVALID_ID if it doesn't exist.
 	 */
-	public static function getIDForScene(sceneName:String):Int
+	public static function getIDForScene(sceneName:String):IdType
 	{
 		for(s in GameModel.get().scenes)
 		{
@@ -1197,7 +1199,7 @@ class Script
 			}
 		}
 		
-		return 0;
+		return IdUtils.INVALID_ID;
 	}
 	
 	/**
@@ -1272,7 +1274,7 @@ class Script
 	 * @param	leave		exit transition
 	 * @param	enter		enter transition
 	 */
-	public static function switchScene(sceneID:Int, leave:Transition=null, enter:Transition=null)
+	public static function switchScene(sceneID:IdType, leave:Transition=null, enter:Transition=null)
 	{
 		engine.switchScene(sceneID, leave, enter);
 	}
diff --git a/com/stencyl/models/GameModel.hx b/com/stencyl/models/GameModel.hx
index 35a84642..fc1564fc 100644
--- a/com/stencyl/models/GameModel.hx
+++ b/com/stencyl/models/GameModel.hx
@@ -7,6 +7,8 @@ import com.stencyl.utils.Utils;
 import com.stencyl.models.scene.Autotile;
 import com.stencyl.models.scene.AutotileFormat;
 
+import com.stencyl.models.IdType.IdUtils;
+
 import box2D.common.math.B2Vec2;
 import box2D.collision.shapes.B2Shape;
 import box2D.collision.shapes.B2PolygonShape;
@@ -26,7 +28,7 @@ class GameModel
 	public var actualHeight:Int;
 	public var scale:Int;
 	
-	public var defaultSceneID:Int;
+	public var defaultSceneID:IdType;
 	
 	public var groups:Array<GroupDef>;
 	public var groupsCollidesWith:Map<Int,Array<Int>>;
@@ -36,7 +38,7 @@ class GameModel
 	public var gameAttributes:Map<String,Dynamic>;
 	public var shapes:Map<Int,B2PolygonShape>;
 	public var atlases:Map<Int,Atlas>;
-	public var scenes:Map<Int,Scene>;
+	public var scenes:Map<IdType,Scene>;
 	public var autotileFormats:Map<Int, AutotileFormat>;
 	
 	public static var INHERIT_ID:Int = -1000;
@@ -65,11 +67,11 @@ class GameModel
 		actualWidth = Std.parseInt(xml.att.awidth);
 		actualHeight = Std.parseInt(xml.att.aheight);
 		scale = Std.parseInt(xml.att.scale);
-		defaultSceneID = 0;
-		
+		defaultSceneID = IdUtils.INVALID_ID;
+
 		try
 		{
-			defaultSceneID = Std.parseInt(xml.att.defaultSceneID);
+			defaultSceneID = IdUtils.parseId(xml.att.defaultSceneID);
 		}
 		
 		catch(e:String)
@@ -164,15 +166,15 @@ class GameModel
 		scenes = readScenes(Data.get().sceneListXML);
 	}
 	
-	public function readScenes(list:Fast):Map<Int,Scene>
+	public function readScenes(list:Fast):Map<IdType,Scene>
 	{
-		var map:Map<Int,Scene> = new Map<Int,Scene>();
+		var map = new Map<IdType,Scene>();
 		
 		for(e in list.elements)
 		{
-			var sceneID = Std.parseInt(e.att.id);
-			
-			map.set(Std.parseInt(e.att.id), new Scene(sceneID, e.att.name));
+			var sceneID = IdUtils.parseId(e.att.id);
+
+			map.set(sceneID, new Scene(sceneID, e.att.name));
 		}
 		
 		Data.get().scenesXML = null;
diff --git a/com/stencyl/models/IdType.hx b/com/stencyl/models/IdType.hx
new file mode 100644
index 00000000..20232a0c
--- /dev/null
+++ b/com/stencyl/models/IdType.hx
@@ -0,0 +1,11 @@
+package com.stencyl.models;
+
+typedef IdType = Int
+
+class IdUtils {
+	public static var INVALID_ID = -1;
+
+	public static function parseId(id: String): IdType {
+		return Std.parseInt(id);
+	}
+}
\ No newline at end of file
diff --git a/com/stencyl/models/Scene.hx b/com/stencyl/models/Scene.hx
index fe361c56..a5ed5fa9 100644
--- a/com/stencyl/models/Scene.hx
+++ b/com/stencyl/models/Scene.hx
@@ -47,7 +47,7 @@ import com.stencyl.utils.PolyDecompBayazit;
 
 class Scene
 {
-	public var ID:Int;
+	public var ID:IdType;
 	public var name:String;
 	
 	public var sceneWidth:Int;
@@ -78,7 +78,7 @@ class Scene
 	
 	public var animatedTiles:Array<Tile>;
 	
-	public function new(ID:Int, name:String)
+	public function new(ID:IdType, name:String)
 	{
 		this.ID = ID;
 		this.name = name;
@@ -1026,7 +1026,7 @@ class Scene
 		return ai;
 	}
 	
-	public function getID():Int
+	public function getID():IdType
 	{
 		return ID;
 	}
diff --git a/com/stencyl/utils/HashMap.hx b/com/stencyl/utils/HashMap.hx
deleted file mode 100644
index e69de29b..00000000
diff --git a/com/stencyl/utils/SizedIntHash.hx b/com/stencyl/utils/SizedIntHash.hx
deleted file mode 100644
index e69de29b..00000000