GitLab

This is useful in case the URL shortening service disappears or breaks.

This is not the right way to install Jupyter if the Python installation
is managed externally (e. g. by Conda or a system package manager).

Made download links more visible, updated some other links and the
stability/compatibility status of the project.

Now hosted at https://www3.hhu.de/stups/downloads/prob2-jupyter/

This can be used when the sys.prefix is not writable, for example when
using the system Python without a virtual environment.

GitLab (or at least this installation) doesn't have a way of uploading
release binaries like GitHub does, so I'm committing the release jar
into the repo (using Git LFS).