make noCountryFlags respect `false` on windows.

[Simon-Laux]

also fix a typo in the documentation

fixes #808 (this implements solution A)

[ThenTech]

I see in your changes that this fix is after if (set == 'native'), but in my testing, if I use a different set, e.g. google and even have an emoji font specified, it also doesn't show the flags. But if I look at the online demo and select google there, the flags do show up...

Edit: I dug a bit deeper in the code, and it looks like you must specify the default set to use in the init function as well (which needs to be called if you want to render emojis with em-emoji). If I only give the data to init, it will default to set="native" and thus never actually use another icon set, even though the Picker has the correct set prop. Using a different font face only does something if you use the native set, but that one then doesn't contain the flags in the first place (on Windows), so you must use a different set either way. So on Windows, providing a different font will never show flags.