Add some comments and fix nuget

MvvmHelpers.nuspec

@@ -8,7 +8,6 @@
        <owners>James Montemagno</owners>
        <licenseUrl>https://raw.githubusercontent.com/jamesmontemagno/mvvm-helpers/master/LICENSE.md</licenseUrl>
        <projectUrl>https://github.com/jamesmontemagno/mvvm-helpers</projectUrl>
-       <iconUrl></iconUrl>
        <requireLicenseAcceptance>false</requireLicenseAcceptance>
        <description>
          Collection of Mvvm Helpers such as ObservableRangeCollection, BaseViewModel, Grouping, and others.
@@ -22,8 +21,7 @@
    </metadata>
    <files>
   <!--Core-->
-     <file src="MvvmHelpers\bin\Release\MvvmHelpers.dll" target="lib\portable-net45+wp8+wpa81+win8+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10\MvvmHelpers.dll" />
-     <file src="MvvmHelpers\bin\Release\MvvmHelpers.xml" target="lib\portable-net45+wp8+wpa81+win8+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10\MvvmHelpers.xml" />
-     <file src="MvvmHelpers\bin\Release\MvvmHelpers.pdb" target="lib\portable-net45+wp8+wpa81+win8+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10\MvvmHelpers.pdb" />
+     <file src="MvvmHelpers/bin/Release/MvvmHelpers.dll" target="lib\portable-net45+wp8+wpa81+win8+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10\MvvmHelpers.dll" />
+     <file src="MvvmHelpers/bin/Release/MvvmHelpers.xml" target="lib\portable-net45+wp8+wpa81+win8+MonoAndroid10+MonoTouch10+Xamarin.iOS10+UAP10\MvvmHelpers.xml" />
    </files>
 </package>

MvvmHelpers/Grouping.cs

@@ -3,15 +3,26 @@
 
 namespace MvvmHelpers
 {
-    public class Grouping<T, TV> : ObservableCollection<TV>
+    /// <summary>
+    /// Grouping of items by key into ObservableRange
+    /// </summary>
+    public class Grouping<T, TV> : ObservableRangeCollection<TV>
     {
+        /// <summary>
+        /// Gets the key.
+        /// </summary>
+        /// <value>The key.</value>
         public T Key { get; private set; }
 
+        /// <summary>
+        /// Initializes a new instance of the Grouping class.
+        /// </summary>
+        /// <param name="key">Key.</param>
+        /// <param name="items">Items.</param>
         public Grouping(T key, IList<TV> items)
         {
             Key = key;
-            foreach (var item in items)
-                Items.Add(item);
+            AddRange(items);
         }
     }
 }

MvvmHelpers/ObservableObject.cs

@@ -5,6 +5,9 @@
 
 namespace MvvmHelpers
 {
+    /// <summary>
+    /// Observable object with INotifyPropertyChanged implemented
+    /// </summary>
     public class ObservableObject : INotifyPropertyChanged
     {
         /// <summary>
@@ -30,7 +33,9 @@ protected bool SetProperty<T>(
             return true;
         }
 
-
+        /// <summary>
+        /// Occurs when property changed.
+        /// </summary>
         public event PropertyChangedEventHandler PropertyChanged;
         /// <summary>
         /// Raises the property changed event.

MvvmHelpers/Utils.cs

@@ -3,8 +3,18 @@
 
 namespace MvvmHelpers
 {
+    /// <summary>
+    /// Extension Utils
+    /// </summary>
     public static class Utils
     {
+        /// <summary>
+        /// Task extension to add a timeout.
+        /// </summary>
+        /// <returns>The timeout.</returns>
+        /// <param name="task">Task.</param>
+        /// <param name="duration">Duration.</param>
+        /// <typeparam name="T">The 1st type parameter.</typeparam>
         public async static Task<T> WithTimeout<T>(this Task<T> task, int duration)
         {
             var retTask = await Task.WhenAny(task, Task.Delay(duration))