Merge pull request #1 from deflaux/master

An initial stab at an RDD for Variant Store.
Yeah, if you read the comment at the top of the file - if those classes you linked to implemented `Serializable` we wouldn't need any of this. 

Unfortunately, I don't think those auto generated classes will change any time soon :(
I was hoping we could instead serialize to json and back for these classes - which is supported by the client library. If we could make that work we wouldn't need to maintain any special code nor configs.