additional parameters for get_clients are not working

[markotmattila]

If one adds additional parameters to the get_clients request, the query url gets deformed. Line 21 of client.py should be

url = self.base_url + '/workspaces/' + workspace_id + '/clients?' + url_params"

instead of

url = self.base_url + '/workspaces/' + workspace_id + '/clients&' + url_params