Typo.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1447752 13f79535-47bb-0310-9956-ffa450edef68
Added a conversion from RotationDS to Rotation.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1447753 13f79535-47bb-0310-9956-ffa450edef68