Make the facades a no-op on Windows platforms, so they don't troll PCL authors
Make the facades a no-op on Windows platforms, so they don't troll PCL authors

tpurtell/ModernHttpClient,paulcbetts/ModernHttpClient,xamarin/ModernHttpClient,leonardors/ModernHttpClient,tomgilder/OkHttpClient,nachocove/ModernHttpClient,kensykora/ModernHttpClient,djlewisxactware/ModernHttpClient,mattleibow/ModernHttpClient,scoodah/ModernHttpClient,koltsov-ps/ModernHttpClient,nachocove/ModernHttpClient-demo,tomgilder/OkHttpClient,pacificIT/ModernHttpClient