Remove the 'setToZero()' method, replaced by a 'createZero' constructor.
This is because search in existing code base has shown that 'setToZero()'
was used only for clearing a newly allocated matrix.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1522019 13f79535-47bb-0310-9956-ffa450edef68