Added LICENSE-header.txt in the source archive

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/bcel/trunk@1627901 13f79535-47bb-0310-9956-ffa450edef68
Fixed the checkstyle errors related to the license headers

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/bcel/trunk@1627906 13f79535-47bb-0310-9956-ffa450edef68