Added missing Apache license headers.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1454718 13f79535-47bb-0310-9956-ffa450edef68
Added Apache license headers.

The header has been added to test files, and the corresponding test
updated to ignore the header lines.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1454719 13f79535-47bb-0310-9956-ffa450edef68