Added a logo for the Metro UI in Win8 & IE 10

The size of the image is the same as the image for the Ipad, but don't use the
same image, nor a full color image. Beter use a white monochrome version of the
logo, this will make it blend in with the Metro UI system tiles.

See http://kremalicious.com/add-your-web-site-to-the-windows-8-metro-ui/ for
more information.
Beter handling of the favicon. Based on
http://www.jonathantneal.com/blog/understand-the-favicon/

Each time you create a theme you will have to create several files:

* a ico-file, 32x32, for IE10, which you should save in the document_root
* a png-file, 96x96, for all decenten browsers which support png-favicon, this
can be stored in the theme
* a png-file, 144x144, for the Metro UI, this can be stored in the theme
Use precomposed so we have full control

    It’s perfectly possible to just create one high-resolution icon and use
	that for all devices. In fact, this is how Apple does it. Devices with smaller
	screens or lower display resolutions will automatically resize the icon.

For more information see: http://mathiasbynens.be/notes/touch-icons
Empty images, so they will be replaced
Moved Facebook og:image below the custom one