Fixed #64 - add description, Fixed #70

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

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

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

...deadlocker8/budgetmaster/logic/RepeatingPaymentEntry.java

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

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

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

src/de/deadlocker8/budgetmaster/ui/NewPaymentGUI.fxml

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

.../deadlocker8/budgetmasterserver/main/DatabaseCreator.java

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

.../budgetmasterserver/server/payment/normal/PaymentAdd.java

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

...rserver/server/payment/repeating/RepeatingPaymentAdd.java