Init native library - call this method in the main() method of your app
Param appName = the title for the hidden window
Each app has it's own hidden window that receives the mouse/menu messages for it's Tray Icons
The window title is used by sendWindowsMessage() and isRunning() to identify an app
Checks if there's an instance with hidden window title = appName running
Can be used to detect that another instance of your app is already running (so exit..)
Param appName = the title of the hidden window to search for