* - small with unneeded lv_obj_invalidate() fix in lv_obj_move_foreground() and lv_obj_move_background()
- added lv_obj_move_up() and lv_obj_move_down()
- used new functions in sample 2
- used lv_obj_swap() to shuffle (turn around) list
* solved build error
* added top and bottom buttons in sample