Add more realistic examples of native modules calling WinRT APIs

[asklar]

Add more realistic examples of native modules calling WinRT APIs
Including pointing to our sample native modules and possibly community modules

Originally posted by @asklar in #280 (comment)

[chrisglein]

FancyMath is nice in that it's simple. But too simple if we don't have examples of more Windows-y stuff, calling real WinRT APIs.