Core 1.3.1 and DSL 1.1.6

This release updates to using Bullet Core 1.3.1 and Bullet DSL 1.1.6

This also changes how TypedAvroBulletRecord and UntypedAvroBulletRecords are serialized in Spark. Bullet Spark uses Kryo for serialization and previously would not hook into the Java serialization for the record types above. The record types above used the Java hooks to read and write Avro. With this release, a registrator for Kryo is used to make sure that the underlying record data is serialized using Avro.