Hibernate4

Support of Hibernate 4.1.11.
Replace the direct hibernate O/R mapping in scheduleevent, mailinglist, and whitepages by a JPA O/R mapping with hibernate as JPA implementation. So, yet no codes depend directly on hibernate (excepted on the annotation @DiscriminatorOptions to overcome of some bad behavior in hibernate with entities inheritance using a discriminator column)

Don't forget to merge also the branch Hibernate4 of Silverpeas-Core, Silverpeas-Parent, and Silverpeas-installer-package.