add use region_polygon for do_entrance_counting

[lastrei]

add Specified coordinate point for do_entrance_counting use --region_polygon such as --region_type=vertical --do_entrance_counting --region_polygon 500 300 it's need one pairs of point coords

The line is extended after passing the specified horizontal mode or vertical mode through the specified point

[paddle-bot[bot]]

Thanks for your contribution!

[lyuwenyu]

可以提新的PR到develop