View message source (#541)

* Added view message source

* Change condition to when button available

Wino.Core.UWP/Controls/ControlConstants.cs

@@ -98,6 +98,7 @@ namespace Wino.Core.UWP.Controls
             { WinoIconGlyph.EventRespond, "\uE924" },
             { WinoIconGlyph.EventReminder, "\uE923" },
             { WinoIconGlyph.EventJoinOnline, "\uE926" },
+            { WinoIconGlyph.ViewMessageSource, "\uE943" }
         };
     }
 }

Wino.Core.UWP/Controls/WinoFontIcon.cs

@@ -99,6 +99,7 @@ namespace Wino.Core.UWP.Controls
         EventReminder,
         EventEditSeries,
         EventJoinOnline,
+        ViewMessageSource,
     }
 
     public class WinoFontIcon : FontIcon