Add a simple golang app to load the schema

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@docker.com> (github: SvenDowideit)

@proppy would like to know that the schema we develop can be loaded by a generalised json schema tool, and this one would satisfy.

if you type `make` you'll see that it falls over on the `$ref`'s, and this is not hyper-urgent to deal with yet, but I thought I'd try it, and now that its there, we have something to test progress

:)