Adding comments to some environment model classes

--HG--
branch : dev

src/Orchard/Environment/Configuration/ShellSettings.cs

@@ -1,4 +1,9 @@
 namespace Orchard.Environment.Configuration {
+    /// <summary>
+    /// Represents the minimalistic set of fields stored for each tenant. This 
+    /// model is obtained from the IShellSettingsManager, which by default reads this
+    /// from the App_Data settings.txt files.
+    /// </summary>
     public class ShellSettings {
         public string Name { get; set; }
         public string DataProvider { get; set; }

src/Orchard/Environment/Topology/Models/ShellDescriptor.cs

@@ -2,6 +2,13 @@
 using System.Linq;
 
 namespace Orchard.Environment.Topology.Models {
+
+    /// <summary>
+    /// Contains a snapshot of a tenant's enabled features.
+    /// The information is drawn out of the shell via IShellDescriptorManager
+    /// and cached by the host via IShellDescriptorCache. It is
+    /// passed to the ICompositionStrategy to build the ShellTopology.
+    /// </summary>
     public class ShellDescriptor {
         public ShellDescriptor() {
             EnabledFeatures = Enumerable.Empty<ShellFeature>();

src/Orchard/Environment/Topology/Models/ShellTopology.cs

@@ -1,10 +1,14 @@
 using System;
 using System.Collections.Generic;
-using Orchard.Environment.Configuration;
-using Orchard.Environment.Extensions;
 using Orchard.Environment.Extensions.Models;
 
 namespace Orchard.Environment.Topology.Models {
+
+    /// <summary>
+    /// Contains the information necessary to initialize an IoC container
+    /// for a particular tenant. This model is created by the ICompositionStrategy
+    /// and is passed into the IShellContainerFactory.
+    /// </summary>
     public class ShellTopology {
         public IEnumerable<ModuleTopology> Modules { get; set; }
         public IEnumerable<DependencyTopology> Dependencies { get; set; }
@@ -15,7 +19,6 @@ namespace Orchard.Environment.Topology.Models {
     public class ShellTopologyItem {
         public Type Type { get; set; }
         public Feature Feature { get; set; }
-        public FeatureDescriptor FeatureDescriptor { get; set; }
     }
 
     public class ModuleTopology : ShellTopologyItem {