Asking the user about an update should be only once per version, not every SE site.

[rschrieken]

When we (or really I) push a new version of the script, users get the confirm box pushed in their face:

https://github.com/SO-Close-Vote-Reviewers/UserScripts/blob/master/SECloseVoteRequestGenerator.user.js#L86

Can we at least make this less blocking?

Reported several times in the past but recently by FerryBig: http://chat.stackoverflow.com/transcript/message/34171354#34171354