We don't need the full Vector API for BSP trees.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1554646 13f79535-47bb-0310-9956-ffa450edef68
Typo.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1554647 13f79535-47bb-0310-9956-ffa450edef68