Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Mail.ViewModels/IdlePageViewModel.cs

@@ -1,9 +1,10 @@
 using Wino.Core.Domain.Interfaces;
+using Wino.Core.ViewModels;
 
 namespace Wino.Mail.ViewModels
 {
-    public partial class IdlePageViewModel : BaseViewModel
+    public partial class IdlePageViewModel : CoreBaseViewModel
     {
-        public IdlePageViewModel(IDialogService dialogService) : base(dialogService) { }
+        public IdlePageViewModel(IMailDialogService dialogService)  { }
     }
 }