api(align) save align in style and handle x/y according to it

examples/styles/lv_example_style_2.c

@@ -23,7 +23,7 @@ void lv_example_style_2(void)
     /*Create an object with the new style*/
     lv_obj_t * obj = lv_obj_create(lv_scr_act());
     lv_obj_add_style(obj, LV_PART_MAIN, LV_STATE_DEFAULT, &style);
-    lv_obj_align(obj, NULL, LV_ALIGN_CENTER, 0, 0);
+    lv_obj_center(obj);
 }
 
 #endif