1.17.0

• Introduce AB Testing feature - PR #408
  List/Create/Stop/Delete AB Tests programmatically
  Introduce new Analytics object, wrapper around the
  Analytics API (more methods to come).

• 2 methods about taskID initially available in the Index moved to the Client.
  You could get some taskID from the engine without necessarily have an instance of Index,
  instead of instantiating an index that you won't need, you can now call wait_task and get_task_status on the client.
  The original methods on the index still work and are not deprecated.

  client.wait_ask(index_name, taskID)
  client.get_task_status(index_name, taskID)