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.
I may have misunderstood method chaining.. Why can't all the methods just return WebSiteRetrieverBuilder? I don't understand why you need all the interfaces.

It doesn't make any difference as far as I can tell, except a clutter of interfaces :p