Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Calendar/Views/Abstract/CalendarPageAbstract.cs

@@ -0,0 +1,7 @@
+using Wino.Calendar.ViewModels;
+using Wino.Core.UWP;
+
+namespace Wino.Calendar.Views.Abstract
+{
+    public abstract class CalendarPageAbstract : BasePage<CalendarPageViewModel> { }
+}