Adding MADlib vector operations.

These are basic UDFs which the user will need to interact with MADlib.

Change-Id: Iadcec2376e29d2f73f1bb04d5e695c58d9381952
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2368
Reviewed-by: Victor Bittorf <victor.bittorf@cloudera.com>
Tested-by: jenkins