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/WindowsFormsSample/FancyPopup.xaml.cs

@@ -13,7 +13,7 @@ namespace Samples
         /// The number of clicks on the popup button.
         /// </summary>
         public static readonly DependencyProperty ClickCountProperty =
-            DependencyProperty.Register("ClickCount",
+            DependencyProperty.Register(nameof(ClickCount),
                 typeof (int),
                 typeof (FancyPopup),
                 new FrameworkPropertyMetadata(0));