Notification icons need an icon if they are to appear

While helping this user, I briefly worked with notification icons (NotifyIcon) from PowerShell. It's possible to load the icon image from an ICO file, but this is suboptimal for that user because there weren't any desirable icons in a consistent place on all machines. Omitting the line that sets the Icon property's setting results in no notification at all - apparently there has to be an icon. Fortunately, there is a SystemIcons class that provides a handful of normal system icon objects. Applying one of these makes the notification work and removes the need to keep a loose ICO file around.