Added Platform level README files

2019-08-08 17:53:09 -05:00 · 2019-08-08 17:53:09 -05:00 · 55041ad576
--- a/avalonia/README.MD
+++ b/avalonia/README.MD
--- a/razor/README.MD
+++ b/razor/README.MD
--- a/testing/README.MD
+++ b/testing/README.MD
--- a/uwp/README.MD
+++ b/uwp/README.MD
--- a/winforms/README.MD
+++ b/winforms/README.MD
--- a/wpf/README.MD
+++ b/wpf/README.MD
--- a/xamarin-forms/README.MD
+++ b/xamarin-forms/README.MD