Add no_directory option when saving image to filesystem

[NickT5]

I added a no_directory option so the user can choose if the images will be downloaded and saved in the output directory with no extra "query" directory. This option is false by default.

This is based on the no_directory option from https://google-images-download.readthedocs.io/en/latest/arguments.html

Command line example:

python
from bing_image_downloader import downloader 
downloader.download("cat", limit=2, output_dir='dataset', no_directory=True)

This will save the images in /dataset/ instead of /dataset/cat/