dispose method
Releases everything this controller owns. The page that created the controller calls this from its own
State.dispose(); a subclass that adds its own notifiers overrides this and ends with super.dispose().
Implementation
@override
void dispose() {
entranceController.dispose();
dayHourlyController.dispose();
nightHourlyController.dispose();
dailyCapController.dispose();
weeklyController.dispose();
monthlyController.dispose();
quarterlyController.dispose();
freeMinutesController.dispose();
super.dispose();
}