support updating entity references
when creating a new entity, refresh the xwic fields
Merge branch 'appkit_5.1' of git@github.com:xwic/appkit.git into appkit_5.1

Conflicts:
	de.xwic.appkit.core/src/de/xwic/appkit/core/remote/server/RemoteDataAccessServlet.java
	de.xwic.appkit.core/src/de/xwic/appkit/core/transfer/EntityTransferObject.java
use util