Show the file list in natural sorted order ( f1->f8->f9->f10 instead of f1->f10->f8->f9 ).
Show the file list in natural sorted order ( f1->f8->f9->f10 instead of f1->f10->f8->f9 ).

* labelImg.py
  (natural_sort): New function, copied from S.O.:
  https://stackoverflow.com/questions/4836710/does-python-have-a-built-in-function-for-string-natural-sort?answertab=votes#tab-top
  (scanAllImages): Return the image file list in natural sorted order.

tzutalin/labelImg,tzutalin/labelImg