OCSADV-27: VoTableClient

This is a small PR containing VoTableClient. It uses the http commons client library to produce a method that returns a Future[CatalogProblem \/ ParsedVoResource] after making a call to one of the Gemini catalogs

A few rawtype warnings were removed as well
It's quite clear what is going on here with the `fold` so this is fine. Take this as a topic for discussion more than a request to change anything.  I would tend to use `identity` (from `Predef`) instead of `r => r` but if we're really just mapping something I would do a `leftMap` here.  What do you guys think?  Better to just always use a `fold`?