修复physics register失效问题

source/src/ECS/Components/Physics/Colliders/Collider.ts

@@ -11,7 +11,7 @@ abstract class Collider extends Component{
     public _isRotationDirty = true;
     protected _isParentEntityAddedToScene;
     protected _colliderRequiresAutoSizing;
-    protected _localOffset: Vector2;
+    protected _localOffset: Vector2 = new Vector2(0, 0);
     protected _isColliderRegisterd;
 
     public get bounds(): Rectangle {

source/src/ECS/Scene.ts

@@ -74,7 +74,9 @@ class Scene extends egret.DisplayObjectContainer {
    /** 初始化场景 */
    public initialize(){
       /** 初始化默认相机 */
-      this.camera = this.createEntity("camera").addComponent(new Camera());
+      this.camera = this.createEntity("camera").getOrCreateComponent(new Camera());
+
+      Physics.reset();
 
       if (this.entityProcessors)
          this.entityProcessors.begin();