Merge pull request #43 in ZP/z-push from bugfix/ZP-692-diffstate.php-use-different-cutoff to develop

* commit '9106da1f':
  ZP-692 Add notes and set to false when we don't care about filtertime. Released under the Affero GNU General Public License (AGPL) version 3.
  ZP-692 Different cutoff dates. Released under the Affero GNU General Public License (AGPL) version 3.