Added methods for resizing running jobflows to EmrConnection.
Added a new class, InstanceGroup, with just a __init__ and __repr__.
Added add_instance_groups function to boto.emr.connection. Built some…
… helper methods for it, and added AddInstanceGroupsResponse class to boto.emr.emrobject.
Added method to lookup the types and IDs of instance groups within a …
Add tiny documentation to _get_instance_group_types
added support for modifying an instance group