Fixed findbugs warnings.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1462508 13f79535-47bb-0310-9956-ffa450edef68
Added description of main 3.2 features in the changelog.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1462509 13f79535-47bb-0310-9956-ffa450edef68