Applying patch 1159 to add SSVD to SpectralKMeans. Also minor tweaks to Path structure.

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1455286 13f79535-47bb-0310-9956-ffa450edef68
Updated class javadocs.

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1455287 13f79535-47bb-0310-9956-ffa450edef68