Code modernising (#8)

* Applied some code conventions, used more current language features which should improve readability and making it easier to re-factor / modify. Also fixed some typos in documentation.
* Changes based on PR conversation for the SystemInfo
* Some modifications due to conversations on the PR, especially I removed the FlagsAttribute on the BalloonFlags.
* Removed Silverlight targeting in code.

Hardcodet.NotifyIcon.Wpf/Source/NotifyIconWpf/Util.cs

@@ -175,7 +175,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
             if (streamInfo == null)
             {
                 string msg = "The supplied image source '{0}' could not be resolved.";
-                msg = String.Format(msg, imageSource);
+                msg = string.Format(msg, imageSource);
                 throw new ArgumentException(msg);
             }
 
@@ -277,7 +277,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
         /// <summary>
         /// Returns a dispatcher for multi-threaded scenarios
         /// </summary>
-        /// <returns></returns>
+        /// <returns>Dispatcher</returns>
         internal static Dispatcher GetDispatcher(this DispatcherObject source)
         {
             //use the application's dispatcher by default
@@ -286,7 +286,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
             //fallback for WinForms environments
             if (source.Dispatcher != null) return source.Dispatcher;
 
-            //ultimatively use the thread's dispatcher
+            // ultimately use the thread's dispatcher
             return Dispatcher.CurrentDispatcher;
         }