BatchProcessor: Fix Class Map

Uses an ObjectMap in place of a Dictionary. I'm not sure if this is better or not. I know Dictionaries have been shown to be quite slow, but we're also working with Dynamic key's here, so it might be in the same boat.

src/starling/rendering/BatchProcessor.hx

@@ -14,7 +14,7 @@ import starling.display.Mesh;
 import starling.display.MeshBatch;
 import starling.utils.MeshSubset;
 import starling.utils.ArrayUtil;
-import haxe.ds.Map;
+import haxe.ds.ObjectMap;
 
 /** This class manages a list of mesh batches of different types;
  *  it acts as a "meta" MeshBatch that initiates all rendering.
@@ -183,10 +183,10 @@ class BatchProcessor {
 }
 
 class BatchPool {
-	private var _batchLists:Map<Class<Dynamic>, Array<MeshBatch>>;
+	private var _batchLists:ObjectMap<Dynamic, Array<MeshBatch>>;
 
 	public function new() {
-		_batchLists = new Map<Class<Dynamic>, Array<MeshBatch>>();
+		_batchLists = new ObjectMap();
 	}
 
 	public function purge():Void {
@@ -207,10 +207,10 @@ class BatchPool {
 	}
 
 	public function get(styleType:Class<Dynamic>):MeshBatch {
-		var batchList:Array<MeshBatch> = _batchLists[styleType];
+		var batchList:Array<MeshBatch> = _batchLists.get(styleType);
 		if (batchList == null) {
 			batchList = new Array<MeshBatch>();
-			_batchLists[styleType] = batchList;
+			_batchLists.set(styleType, batchList);
 		}
 
 		if (batchList.length > 0)
@@ -221,7 +221,7 @@ class BatchPool {
 
 	public function put(meshBatch:MeshBatch):Void {
 		var styleType:Class<Dynamic> = meshBatch.style.type;
-		var batchList:Array<MeshBatch> = _batchLists[styleType];
+		var batchList:Array<MeshBatch> = _batchLists.get(styleType);
 		if (batchList == null) {
 			batchList = new Array<MeshBatch>();
 			_batchLists.set(styleType, batchList);