Simplify Registry.prototype.extensionsForType.
Merge pull request #2052 from rwjblue/fixup-extensions-for-type

Simplify Registry.prototype.extensionsForType.
Adds --pod option for blueprints generate and destroy. Adds
`fileMapTokens` to blueprints.
Merge pull request #1994 from trabus/pod-blueprints

Add pod blueprint generators