Reduce the coupling between the builder and the OM implementation.

git-svn-id: https://svn.apache.org/repos/asf/webservices/axiom/trunk@1608290 13f79535-47bb-0310-9956-ffa450edef68
OMSourcedElement: handle forceExpand at a somewhat lower level.


git-svn-id: https://svn.apache.org/repos/asf/webservices/axiom/trunk@1608291 13f79535-47bb-0310-9956-ffa450edef68