MAHOUT-916 - make mahout tests run in parallel

Currently set to class parallel (method parallel fails with our tests at the
moment), set to run 1.5 as many test thread as the machine running them as CPUs.


git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1488632 13f79535-47bb-0310-9956-ffa450edef68