* - 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
Add lv_<widget>_draw_part_type_t to widgets to precisly describe the hooked drawings.
Also add class_p element to lv_obj_draw_part_dsc_t to show what widgets lv_<widget>_draw_part_type_t needs to be used.
Related to: https://forum.lvgl.io/t/how-to-add-minor-division-lines-to-a-chart/5366/