View results settings

This was part of this issue. I don't think it's necessary to add a date field when to show the result though. I think this could be enough:

Display results:
- Always
- After user has voted
- After voting has closed

"Always" might need a more descriptive sentence, but what it basically means it that the user can view the result before it has voted. One way to implement this would be with a result tab as in poll module 5.0. I haven't added "Never" as an option because this is preferable done with a permission. How about changing the unused "view decisions" permission to "view results"?

To keep the setting down a bit (which always is good...) on the create/edit page I suggest that this setting is added as a site-wide setting. If there's a high demand on making it node-specific we could of course re-think this.