added all Notifications for the model view communication

added all required notifications with their content and getter methods.

Projekte/mdga/model/src/main/java/pp.mdga/notification/StartDialogNotification.java

@@ -0,0 +1,12 @@
+package pp.mdga.notification;
+
+/**
+ * Notification that a dialog has been started
+ */
+public class StartDialogNotification extends Notification{
+    /**
+     * Constructor
+     */
+    StartDialogNotification() {
+    }
+}