Ability to parse multi value -c arguments on the commandline

Hi!

The following patch enables lists of values to be parsed on the CLI via the '''-c''' argument.
This way one can configure Nimbus and Supervisors almost entirely from the CLI.

Sample:
'''
bin/storm-mesos nimbus -c java.library.path=native:/usr/local/lib,mesos.master.url=master1:5050,mesos.executor.uri=http://mydomain.com/storm-mesos-0.8.3-wip3.tgz,nimbus.host=myMaster,storm.local.dir=../storm-local,ui.port=7070,storm.zookeeper.servers=zk0,zk1,zk2
''' 

We use it to run Storm on Mesos, but the patch is generic and benefits regular Storm CLI parsing.
I do have tests, but didn't see a standard way to trigger tests for utility functions like this.
Thanks!
-Erich