Improved md5 hash generation; ensure all artifacts including signatures and md5 hashes belong to a common artifact collection (archives)

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/project-release-tools/trunk@1506045 13f79535-47bb-0310-9956-ffa450edef68
Added task to generate svnmucc file for release dist promotion

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/project-release-tools/trunk@1506046 13f79535-47bb-0310-9956-ffa450edef68