Move image save function to AdServiceImpl.
Merge branch flo into master

Conflicts:
	Skeleton/src/main/java/ch/studihome/jspserver/controller/AdpageController.java
	Skeleton/src/main/java/ch/studihome/jspserver/controller/service/AdServiceImpl.java
	Skeleton/src/main/java/ch/studihome/jspserver/model/Advert.java