add suppress for warning

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/utils/Copy.java

@@ -29,6 +29,7 @@ public class Copy {
 	private Copy() {
 	}
 
+	@SuppressWarnings("unchecked")
 	public static <T extends Copyable> T copy(T original) {
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
 		try {