fixes #3960 - wrap APIv2 errors in an "error" node

fixes #3998 - API v2 error on /api/compute_resources, missing gce.json.rabl

fixes #2763 - correcting doco links

fixes #2951 - Host API documentation lacks compute_resource_id

fixes #3256 - include members in usergroup show

fixes #3267 - API v1 compatibility for /api/hosts

fixes #3140 - API to allow importing of puppet classes

fixes #3101 - list available images for CRs, add iam_role field to images API

fixes #3052 - reports#show json rabl template to match as_json output that was removed

fixes #2969 - remove all legacy api code in UI controllers, add deprecation response