Fixed AvalonDock close tools crash, added Block Output Preview pane

Filtration/WindsorInstallers/ViewModelsInstaller.cs

@@ -3,6 +3,7 @@ using Castle.MicroKernel.Registration;
 using Castle.MicroKernel.SubSystems.Configuration;
 using Castle.Windsor;
 using Filtration.ViewModels;
+using Filtration.ViewModels.ToolPanes;
 
 namespace Filtration.WindsorInstallers
 {
@@ -50,6 +51,11 @@ namespace Filtration.WindsorInstallers
                     .ImplementedBy<BlockGroupBrowserViewModel>()
                     .LifeStyle.Singleton);
 
+            container.Register(
+                Component.For<IBlockOutputPreviewViewModel>()
+                    .ImplementedBy<BlockOutputPreviewViewModel>()
+                    .LifeStyle.Singleton);
+
             container.AddFacility<TypedFactoryFacility>();
             container.Register(
                 Component.For<IItemFilterBlockViewModelFactory>().AsFactory());