Don't use leading slashes for patterns in zipfileset.  PR 53949

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1554808 13f79535-47bb-0310-9956-ffa450edef68
assorted micro-optimizations by Adrian Nistor - 13 different Bugzilla issues

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@1554813 13f79535-47bb-0310-9956-ffa450edef68