Everything updated to support user/admin choice of displaying the AJAX...

... warning message for leaving the page, defaults to on. Tested working in all situations (general usage, installing, updating) except when editing admin details, a commented out updated query in admin_actions.php from line 45 shows the attempted query which results in silent failure on the edit page. User updating is working fine however.

I'm sure you can easily figure out what needs doing to fix the admin edit problem, hence the pull request.