QuickReload: pollingDelay is not reset when becoming active again

If the Confluence.QuickReload.SmartTimer deems that you are no longer active, and it starts to back off the polling, then when you return to activity (by firing the focus or click events registered), it will reschedule the next poll using the old pollingDelay (which is a large delay, at this point), before resetting the lastActivityMs value.

slancashire, this is the issue we discussed in Hipchat. I have a PR forthcoming.