Additions to newmail_notifier

Hi,
in addition to ken-hk's work submitted in #84, this extends the basic (favicon) notification method to make use of Internet Explorer's overlay icon feature when in Pinned site mode.
In order for the Pinned site icon to look better, I've also added additional resources with different sizes to the favicon.ico files in both Classic and Larry themes (otherwise the icon would have been framed in a white square, and that doesn't look very attractive).
The screenshot of the effect of this patch can be seen here:
![screenshot.](http://i.imgur.com/QdavgI6.png)
Note that this not only adds the overlay, but also tells IE to blink its Taskbar button.