Revert "Update to Spark 1.0.2 and sbt 0.13.5"

This reverts commit 51b7831c6de7586a00ba598dbbf5cdda9ca6902c.
Revert "Upgrade Spark to version 1.0.0 and bump sbt to 0.13.5"

This reverts commit c3492ba2961356266b4ef00a17a92354992e638a.