fix #1123 rename History `onpopstate` event to `popstate`

I tweaked the commit from @benouat from #1123 to add some changes that were not done, and additionally deprecate the old event.

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This change has been done to be more compliant with the standard HTML5 spec.
Both events are still present, and both of them are fired when needed.

The `onpopstate` event is deprecated and will be removed in the future.

Close #1224.