Fixed #192 - fix correct usage of Controller getParentStage

...ocker8/budgetmaster/ui/controller/CategoryController.java

...adlocker8/budgetmaster/ui/controller/ChartController.java

...de/deadlocker8/budgetmaster/ui/controller/Controller.java

...er8/budgetmaster/ui/controller/NewCategoryController.java

...ker8/budgetmaster/ui/controller/NewPaymentController.java

...locker8/budgetmaster/ui/controller/PaymentController.java

...dlocker8/budgetmaster/ui/controller/ReportController.java

...ocker8/budgetmaster/ui/controller/SettingsController.java

...r8/budgetmaster/ui/controller/SplashScreenController.java