Modified for Spark 1.1.0

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.
Merge pull request #1 from agrinh/spark_1_1_0_compatible

Modified for Spark 1.1.0