content-api-scala-client: Adding item options to scala client.

     - Upgrading java version to 1.7.
     - Enforcing users to use scala version  2.11.2. (Removing support for multiple versions given the need to add more than 22 fields to a case class)
Yeah I was going to remove this, but Mariot said to leave it in for if we decide to have crossScalaVersions in the future.