Updaing project types, adding test programs

csharp/Facebook.Yoga.App/Facebook.Yoga.Universal.App/MainPage.xaml

@@ -0,0 +1,13 @@
+<Page
+    x:Class="Facebook.Yoga.App.MainPage"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Facebook.Yoga.App"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d">
+
+    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+        <TextBlock x:Name="textBlock" Margin="25"/>
+    </Grid>
+</Page>