Fixes #9162: add mention of Windows Phone 8 and IE10 bugs with responsive foo

I'm torn on including this much, but I figured it makes sense. Also, Tim's post at http://timkadlec.com/2013/01/windows-phone-8-and-device-width/ makes a good argument in favor of at least having this around (that basically being WinPh8 and IE10 is a new and emerging market and we should support it).

/cc @robowerks @cvrebert