Missing 'object diff' method

[rememberberry]

It seems the api is missing the object diff method. As easy as:

def object_diff(self, hash_a, hash_b, **kwargs):
  args = (hash_a, hash_b)
  return self._client.request('/object/diff', args, decoder='json', **kwargs)

[whereswaldon]

Looks great. If you'd like to write a test for it, we'd be happy to include in as a PR. Thanks!

[mike7c2]

I was looking for this functionality as well, I didn't think to look here before making the change and adding a test, please see:

#219