Limiting form responses to one per person is now a simple matter of checking the box labeled "only allow response per person." That option appears above the title of your form.
Randomizing the sequence in which questions appear on your Google Forms is now just a matter of clicking the box labeled "shuffle question order." With that box selected each person viewing your form will see the questions in a different sequence.
|Click the image to view it in full size.|
There were some other new, but less significant, features added to Google Forms today. Those features include shortened URLs for sharing Forms, the option to search with the help menu, and limiting "grid style" questions to one response.