New BussTUC plugin and several utils and fixes.

Add BussTUCPlugin with support for BusTUC by IDI. Add jSoup-based website-retriever. Add utils for general purpose use. Clean some junk. Fix settings file not being generated if not existing.
If you are wondering why we have an interface with callbacks, it's to avoid these ridiculous exception on runtime. With an interface, there is no need for reflection, and we don't get these kinds of bugs. There's no real need for reflection in this.