Some parameters for annotation list retrieval not implemented

[franfabrizio]

I noticed that the Annotations.list() method supports modified_since and deleted_since (and limit indirectly via the page_size parameter), but not group_id or document_id.

Was this intentional, an oversight, or just a "haven't gotten to it yet"? I am considering forking and adding, but I would have to familiarize myself with how to do the tests and such, I don't often develop in Python so this would be a time and effort commitment for me, which is fine but if it's a 5 minute fix on your end, that's probably better. :-)

Thanks!