Added a new LayersIterator class

This class iterates recursively over layers, flattening groups.
This enables us to simplify the code when we iterate layers. We can remove all recursive function calls in the GameScene code (it is delegated to the LayersIterator)

front/src/Phaser/Map/ITiledMap.ts

@@ -14,7 +14,7 @@ export interface ITiledMap {
      * Map orientation (orthogonal)
      */
     orientation: string;
-    properties: ITiledMapLayerProperty[];
+    properties?: ITiledMapLayerProperty[];
 
     /**
      * Render order (right-down)
@@ -24,6 +24,11 @@ export interface ITiledMap {
     tilewidth: number;
     tilesets: ITiledTileSet[];
     version: number;
+    compressionlevel?: number;
+    infinite?: boolean;
+    nextlayerid?: number;
+    tiledversion?: string;
+    type?: string;
 }
 
 export interface ITiledMapLayerProperty {
@@ -38,19 +43,35 @@ export interface ITiledMapLayerProperty {
     value: boolean
 }*/
 
-export interface ITiledMapLayer {
+export type ITiledMapLayer = ITiledMapGroupLayer | ITiledMapObjectLayer | ITiledMapTileLayer;
+
+export interface ITiledMapGroupLayer {
+    id?: number,
+    name: string;
+    opacity: number;
+    properties?: ITiledMapLayerProperty[];
+
+    type: "group";
+    visible: boolean;
+    x: number;
+    y: number;
+    /**
+     * Layers for group layer
+     */
+    layers: ITiledMapLayer[];
+}
+
+export interface ITiledMapTileLayer {
+    id?: number,
     data: number[]|string;
     height: number;
     name: string;
     opacity: number;
-    properties: ITiledMapLayerProperty[];
-    encoding: string;
+    properties?: ITiledMapLayerProperty[];
+    encoding?: string;
     compression?: string;
 
-    /**
-     * Type of layer (tilelayer, objectgroup)
-     */
-    type: string;
+    type: "tilelayer";
     visible: boolean;
     width: number;
     x: number;
@@ -59,13 +80,29 @@ export interface ITiledMapLayer {
     /**
      * Draw order (topdown (default), index)
      */
-    draworder: string;
-    objects: ITiledMapObject[];
+    draworder?: string;
+}
+
+export interface ITiledMapObjectLayer {
+    id?: number,
+    height: number;
+    name: string;
+    opacity: number;
+    properties?: ITiledMapLayerProperty[];
+    encoding?: string;
+    compression?: string;
+
+    type: "objectgroup";
+    visible: boolean;
+    width: number;
+    x: number;
+    y: number;
 
     /**
-     * Layers for group layer
+     * Draw order (topdown (default), index)
      */
-    layers: this[];
+    draworder?: string;
+    objects: ITiledMapObject[];
 }
 
 export interface ITiledMapObject {