Generate the different layers 'stencil_x.jpg' to the same output folder that the final image

[garaud]

When you use the stencil function such as:

from pycht import Pycht

Pycht().stencil("jazz.jpg", nb_colors=3, output_path="./images")

This generates the stencil_final.jpg image into the output ./images but the other intermediate layers are still in the current folder (where the python interpreter was lunched).

Note that we can have a prefix which can be the same input image name with a specific suffix. Example:

./images/
 - jazz-stencil_1.png
 - jazz-stencil_2.png
 - jazz-stencil_3.png
 - jazz-stencil_final.jpg

It can be useful if I want to have a folder with different output files from different input images.