Input & output validation with api-docs (swagger)

Optional & pluggable, for handlers, maybe also for middleware. Schema is awesome and proven per today, Spec is the probable future. I could pull out a proposal for a common structure for input & output coercion with api-docs, based on our libs.

• simple, data-driven core
• optionally "easy" macro sugar with inferred models
• pluggable implementation (schema, spec, other)
• protocols for routing libs to collect routes for api-docs
• swagger-docs (ring/spec-swagger)

what do you think?