Better wording

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1553847 13f79535-47bb-0310-9956-ffa450edef68
Document java version requirement on main page

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1553848 13f79535-47bb-0310-9956-ffa450edef68