PCN Spec specified according to JSON Schema specification

I wrote the PCN Spec in [JSON Schema](http://json-schema.org/) format. JSON Schema is a draft standard approved by the IETF for specifying the format of JSON documents. Using this schema, a PCN Spec document can be validated using tools written in 14 languages. [Other tools](http://json-schema.org/implementations.html) such as UI generators are also available.

You can try it out using this tool:
http://json-schema-validator.herokuapp.com/