removed HorribleProxy
added current version of BouncyCastle and xmlsec (using xmlsec instead of jdk internal classes, because of interoperabiltiy with e.g. IBM JDK)
heaps of changes because of above

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/xml_signature@1620230 13f79535-47bb-0310-9956-ffa450edef68