Make number of dimensions for PCA an input argument
Added ivyXML dependency to fix orbit bug

See
http://mail-archives.apache.org/mod_mbox/spark-user/201309.mbox/%3CCAJbo
4neXyzQe6zGREQJTzZZ5ZrCoAvfEN+WmBYCed6N1EPftxA@mail.gmail.com%3E
Added default parallelism specification for cluster
Merge branch 'master' of https://github.com/freeman-lab/thunder