* Allow to start tests with old Xerces jar-file to trigger issues we saw with missing methods in this XML parser. This is only active if the location of the jar-file is provided via ant property "-Dadditionaljar=lib/xercesImpl-2.6.1.jar"
* Also remove dom4j from downloaded libs to fully get rid of it in build-environments

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1618610 13f79535-47bb-0310-9956-ffa450edef68