Modified INavigationTyopicViewModel<T> to derive from ITopicViewModel

`IPageTopicViewModel` and, more broadly, `PageTopicViewModel`, bring with them a bit of overhead, such as metadata fields and body, which increase processing time and memory, with little expected benefit. Mitigated this by trimming down the `NavigationTopicViewModel` class and its associated interface.

Author: JeremyCaney

Ignia.Topics.ViewModels/NavigationTopicViewModel.cs

@@ -26,8 +26,10 @@ namespace Ignia.Topics.ViewModels {
   ///     cref="NavigationTopicViewModel"/> class is marked as <c>sealed</c>.
   ///   </para>
   /// </remarks>
-  public sealed class NavigationTopicViewModel : PageTopicViewModel, INavigationTopicViewModel<NavigationTopicViewModel> {
+  public sealed class NavigationTopicViewModel : TopicViewModel, INavigationTopicViewModel<NavigationTopicViewModel> {
 
+    public string WebPath { get; set; }
+    public string ShortTitle { get; set; }
     public Collection<NavigationTopicViewModel> Children { get; set; }
     public bool IsSelected(string uniqueKey) => uniqueKey?.StartsWith(UniqueKey) ?? false;
 

Ignia.Topics.Web.Mvc/Models/NavigationViewModel{T}.cs

@@ -20,13 +20,13 @@ namespace Ignia.Topics.Web.Mvc.Models {
   ///     constructed by the <see cref="LayoutController"/>.
   ///   </para>
   ///   <para>
-  ///     The <see cref="NavigationRoot"/> can be any view model that implements <see cref="INavigationTopicViewModelCore"/>,
+  ///     The <see cref="NavigationRoot"/> can be any view model that implements <see cref="INavigationTopicViewModel"/>,
   ///     which provides a base level of support for properties associated with the typical <c>Page</c> content type as well as
-  ///     a method for determining if a given <see cref="INavigationTopicViewModelCore"/> instance is the currently-selected
-  ///     topic. Implementations may support additional properties, as appropriate.
+  ///     a method for determining if a given <see cref="INavigationTopicViewModel"/> instance is the currently-selected topic.
+  ///     Implementations may support additional properties, as appropriate.
   ///   </para>
   /// </remarks>
-  public class NavigationViewModel<T> where T: IPageTopicViewModel {
+  public class NavigationViewModel<T> where T: INavigationTopicViewModel<T> {
 
     public T NavigationRoot { get; set; }
     public string CurrentKey { get; set; }

Ignia.Topics/ViewModels/INavigationTopicViewModel{T}.cs

@@ -17,7 +17,24 @@ namespace Ignia.Topics.ViewModels {
   ///   No topics are expected to have a <c>Navigation</c> content type. Instead, implementers of this view model are expected
   ///   to manually construct instances.
   /// </remarks>
-  public interface INavigationTopicViewModel<T> : IPageTopicViewModel where T: INavigationTopicViewModel<T> {
+  public interface INavigationTopicViewModel<T> : ITopicViewModel where T: INavigationTopicViewModel<T> {
+
+    /*==========================================================================================================================
+    | PROPERTY: WEBPATH
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Represents the HTTP routing path for the corresponding <see cref="Topic"/>.
+    /// </summary>
+    string WebPath { get; set; }
+
+    /*==========================================================================================================================
+    | PROPERTY: SHORT TITLE
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   In addition to the Title, a site may opt to define a Short Title used exclusively in the navigation. If present, this
+    ///   value should be used instead of Title.
+    /// </summary>
+    string ShortTitle { get; set; }
 
     /*==========================================================================================================================
     | PROPERTY: CHILDREN