Global Functions
- application()
- Returns the Application instance. The first time an instance of Application
or a subclass of Application is created, a global reference to it is stored;
the application function returns this reference.
- If this function is called before any Application object has been created,
it creates an instance of class Application automatically.
- run()
- Runs the application. This is equivalent to application().run(). Retains control until the application is quit.