OPENJPA-2172.  Remove the dependency on the slf4j runtime bundle from openjpa-all.jar.  Also, modified the persistence.xml files for the OpenBooks sample to set the Validation-Mode to None (since it's not being used).  This way, we can avoid the dependency altogether.  This also required the update to the persistence.xml files to point at the JPA 2.0 xsd files.

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@1468108 13f79535-47bb-0310-9956-ffa450edef68