MAHOUT-961: fix issues with visualizing DF trees

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1489802 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-916 reduce max JVM heap during parallel tests to avoid thrashing from over-committed memory

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1489827 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1240 correcting the randomized testing jar version to be same as in math

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1490110 13f79535-47bb-0310-9956-ffa450edef68