Move the removeChildren code to the core model.

git-svn-id: https://svn.apache.org/repos/asf/webservices/axiom/trunk@1611862 13f79535-47bb-0310-9956-ffa450edef68
Work around build failure.

git-svn-id: https://svn.apache.org/repos/asf/webservices/axiom/trunk@1611863 13f79535-47bb-0310-9956-ffa450edef68
Enabled W3C test case that actually works.

git-svn-id: https://svn.apache.org/repos/asf/webservices/axiom/trunk@1611869 13f79535-47bb-0310-9956-ffa450edef68