core.py
- removed unused import of shutil
- improved try: for creating directory, but still wrong style: We cannot
    do any "print()" here - we have not ui here.
ui/console.py
- new test if provided path is a directory
- console_rotate_pics:
  - do not rewrite already provided list of pictures if user newly provide
    an empty list (which means, preserver previous list).
  - rotate pics only if user confirm everything o.k.
Removed TODO for finished work.
README improved with an example.