Default settings in save method requires a client

When just trying to save a cube with gordias save() and default settings, it failes if there is no client. It crash when trying to run:

 r = client.compute(data)
 progress(r)

By using the flag iterative_storage=True one can go around it and store the result without a client. Maybe we should think about the default behaviour or allow the user to store the result without a client.