Changelog:
- End times are now also parsed, additional to the start times.
- Original time strings are now ommited since they are already very reliable to parse.
- JSON files are now human-readable.
To me, it's still unclear which timezone is used for the dates. On my Raspberry, these are local times (the behavior I expect), but on my PC they are -1 hour (which currently is UTC). If someone has an idea how to handle this properly, let me know.