Adds Otter (Rackspace Autoscale) to labs https://issues.apache.org/jira/browse/JCLOUDS-215
JCLOUDS-215 - Adds Group configuration, Group launch, Scaling policy functionality
JCLOUDS-215 - Adds Webhook and Execution support to autoscale
Fixes autoscale version to 1.6.3 for backport