rest: oops, remove bad require
rest: add default_printer_name to devices
rest: add preferred_language to users
rest: implement language fallbacks for users
rest: implement ppd links for printer queues
rest: add class store tests
rest: implement computed attributes
rest: use blocks to create class_store defaults
rest: implement ignore_attr
rest: use ignore_attr&computed_attr to cleanly add ppd_link to
printer queues