correct revhistory in both books: 08-13 was preview, not UA
in Overview section, replace several occurrences of hard-coded Autoscaling with entity &PROD;
update staged RBAC section to current standard, consistent with other Rackspace API doc
fix fix to revhistory: 08-13 is Early Access, not Preview, not UA
Merge pull request #363 from rackerlabs/TWrose-RBAC

update staged RBAC section to match current common language