Added missing header.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1454441 13f79535-47bb-0310-9956-ffa450edef68
Removed redundant public modifiers.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1454442 13f79535-47bb-0310-9956-ffa450edef68