Merge pull request #1 from deflaux/master

An initial stab at an RDD for Variant Store.
@cassiedoll, Based on the following links, by looking at the return types of the methods, it seems that the classes most likely must have the types already defined:

https://developers.google.com/resources/api-libraries/documentation/genomics/v1beta/java/latest/com/google/api/services/genomics/model/Call.html

https://developers.google.com/resources/api-libraries/documentation/genomics/v1beta/java/latest/com/google/api/services/genomics/model/Variant.html

It probably would be more automatic to just have a lookup and assign the appropriate type automatically, otherwise a config file might be necessary.

Hope it helps,
Paul