minor fixes
minor fixes

- watch out for empty updates on PUT's
- pass synchronize_session=False on update and delete

andymcguinness/Planet-Lab,freedomgames/Planet-Lab,nicktimko/Planet-Lab,nicktimko/Planet-Lab,andymcguinness/Planet-Lab,andymcguinness/Planet-Lab,freedomgames/Planet-Lab,nicktimko/Planet-Lab,nicktimko/Planet-Lab,freedomgames/Planet-Lab