Add support for process grouping status check.

PLEASEREVIEW: @gwatts @declanshanaghy @edsplunk @nsamad

Added support for process status for grouping when celery processes different queue on different workers.
Celery processes name will be:
%(group_name)s:%(program_name)s:%(process_num)s

@see http://supervisord.org/configuration.html#group-x-section-settings

ex)storm is group name, and shows up in the celery process status as:
storm:celeryd-main               RUNNING    pid 13530, uptime 0:00:05
storm:celeryd-migration          RUNNING    pid 13526, uptime 0:00:05
storm:celeryd-recover            RUNNING    pid 13532, uptime 0:00:05
storm:celeryd-transient          RUNNING    pid 13533, uptime 0:00:05
storm:celeryd-upload             RUNNING    pid 13527, uptime 0:00:0