Make Inbox count autorefresh work on new boards

[fracture91]

The number of unread messages appears on the top and bottom of the page next to "Inbox". This should autorefresh like PM count autorefresh did on the old boards. The best plan is probably to take a look at the XHR XenForo makes when you hover over the inbox link, and try to mimic that to get the needed info. Should also update the inbox popups if we can.

Alternate source: http://apis.ign.com/boards/api/user.json?username=gamerX1011