Improved performance, YAML resource upload

This release adds significant performance improvements to listings of large collections and a new support for wildcards when listing revisions (this allows spec and deployment revisions to be listed across multiple versions and APIs). Along with other small bug fixes and general cleanup, it includes a new apply subcommand of the registry tool that is designed to work like kubectl apply. This allows APIs and artifacts to be uploaded to a registry from YAML source files, and will likely be extended to directly support all resource types (currently deployments, versions, and specs can be uploaded as subresources of APIs).

One field in specs was removed: revision_tags, which returns the tags used to tag a particular revision. We found this costly to maintain and rarely (if ever) used, so we've removed that and are open to discussions of alternate ways to obtain this information.