Riak2.0 driver changes, scalaz 7.1, scala 2.1

The riak2.0 driver uses java Future to perform operations. There are various changes in the API. Read this blog entry. 

This fix moves `scalaz to 7.1`, and complies with `scala 2.11` as well. 
`mockito` is removed as the riak2.0 driver uses a builder approach to create stuff and the classes aren't exposed.