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 returned WebSiteRetrieverBuilder with all it's functions you could leave the building process unfinished before calling fetch(). For example you could do this: new WebSiteRetrieverBuild().setUrl("http://google.com").fetch(); which wouldn't do you much good. Introducing interfaces as return types ensures that the user can not make this mistake, and only allows for a valid object to be created.