Version 2.4.6

Change log:

• Added module test_utils with utilities for writing unit tests and adjusted to work with sentinelhub-py package.
• Added a new parameter to OgcRequest.create_request and GeopadiaImageRequest.create_request methods. By default this parameter will keep existing feature iterator class, if it exists, and therefore prevent re-running a request to services when re-calling create_request method.