修复physics register失效问题

source/src/Utils/RectangleExt.ts

@@ -0,0 +1,16 @@
+class RectangleExt {
+    public static union(first: Rectangle, point: Point){
+        let rect = new Rectangle(point.x, point.y, 0, 0);
+        return this.unionR(first, rect);
+    }
+
+    public static unionR(value1: Rectangle, value2: Rectangle){
+        let result = new Rectangle();
+        result.x = Math.min(value1.x, value2.x);
+        result.y = Math.min(value1.y, value2.y);
+        result.width = Math.max(value1.right, value2.right) - result.x;
+        result.height = Math.max(value1.bottom, value2.bottom) - result.y;
+
+        return result;
+    }
+}