Modified for Spark 1.1.0

I'm not sure how you intend to support different versions of Spark but here's a small commit to support Spark 1.1.0 instead of the older 1.0.x versions. It works fine for me but I did not look too closely for issues!

Commit msg
-----------------
Due to a small change in ShuffledRDD's template parameters introduced in
Spark 1.1.0 the code became incompatible with Spark 1.1.0. This commit
simply ensures the correct type parameters are sent to the ShuffledRDD
and modifies the build.sbt dependency to Spark 1.1.0.