Experimentation and notes
Experiment now works with all existing tests
Note recursion path
Track recursion depth
Match on entity name path
Satisfy rubocop and remove some unused code
Added default behavior, show all fields
Pass new params and handle the levels param
Handle fields=some:relationship
Handle fields=entity_type.field_name.*
Handle explicit fields=entity_type.field_name
Suppress rubocop temporarily
Convert @allowed_ lists to hashes
fields should not mention root entity_type
When fields= is used, default to no relationships
Figure out when to append ".*" to fields

Also, allow "fields=*"
Allow fields=parent_id explicitly
Some comment cleanup and code refactoring
More comment cleanup and code refactoring
parent_id to default output