Version 1.2.0

• On PyPI: the program can be installed with pipx install neural-network-digits (or
  pip install neural-network-digits) and started with the neural-network-digits command, on Windows,
  Linux and macOS. Installed like this, the photos, the model and the settings go in the folder of the user,
  and the program tells you to update with pipx upgrade neural-network-digits.
• The code is now in the nn_digits folder. start.bat, ./start.sh and python start.py work as before,
  and python -m nn_digits works too. Updating from the program moves the files by itself: your photos,
  model and settings in data/ stay where they are.
• The windows that talk about the photos show the folder where they really are.
• Discussions are open on GitHub for questions and ideas, and there is a Sponsor button.