Updating demo to use the markup extension

Author: Keboo

MainDemo.Wpf/MainWindow.xaml

@@ -12,7 +12,8 @@
         TextOptions.TextFormattingMode="Ideal" 
         TextOptions.TextRenderingMode="Auto"
         Background="{DynamicResource MaterialDesignPaper}"
-        FontFamily="{StaticResource MaterialDesignFont}" Icon="favicon.ico">
+        FontFamily="{materialDesign:MaterialDesignFont}" 
+        Icon="favicon.ico">
     <Window.CommandBindings>
         <CommandBinding Command="Copy" Executed="OnCopy"></CommandBinding>
     </Window.CommandBindings>