no need to cast twice asSubclass

git-svn-id: https://svn.apache.org/repos/asf/geronimo/xbean/trunk@1617085 13f79535-47bb-0310-9956-ffa450edef68
easy way to avoid duplicates in findImplementations, real fix needs really more refactoring so ok for now

git-svn-id: https://svn.apache.org/repos/asf/geronimo/xbean/trunk@1617090 13f79535-47bb-0310-9956-ffa450edef68