refactor model instantiation to use factory methods instead of crud_controller method (should make code easier to understand)
refactored controller edit process -- removed helper function from crud_controller base class and put flow logic back into individual controllers themselves (should make the logic easier to understand and customize when needed)
refactored all model instantiation to use factory method (to make code more consistent)
removed some potentially dangerous utility methods from controllers -- now data will never be deleted upon package uninstallation, and you must bump up the package version number and upgrade via dashboard to refresh the schema
change INNER JOINs to LEFT JOINs in car model to facilitate potentially non-required associations
added sample blocktype