Controller JSON Schema

Original Message:
Added JSON Schemas, however the descriptions need to be updated.

Update:
I've updated the types and tried to optimize the definitions. All the commit messages were update to match the current style.

Update.2:
Signed off all commits and changed author to my real name.
`started` is not a valid value, it may be one of `starting`, `up`, `down`, or `crashed` (see [controller/schema.go](https://github.com/flynn/flynn/blob/fce9d98443d4e1d41c872bbbc8f6bd9328c96f68/controller/schema.go#L102))