implemented updating normal and repeating payments

src/de/deadlocker8/budgetmaster/logic/ServerConnection.java

src/de/deadlocker8/budgetmaster/ui/NewPaymentController.java

src/de/deadlocker8/budgetmaster/ui/cells/PaymentCell.java

.../deadlocker8/budgetmasterserver/main/DatabaseHandler.java

...de/deadlocker8/budgetmasterserver/server/SparkServer.java

...dgetmasterserver/server/payment/normal/PaymentUpdate.java

...tmasterserver/server/updater/RepeatingPaymentUpdater.java