ATMO-294 Improve performance of monitor_instances.

* The old monitor_instances used too many resources and was
  too slow.
* The new monitor_instances doesn't need to work with Euca!
* Currently takes approximately 20 seconds down from > 2 minutes.

	modified:   service/tasks/allocation.py
Merge branch 'master' of github.com:iPlantCollaborativeOpenSource/atmosphere

Conflicts:
	service/tasks/allocation.py