implement schema generation and validation

[titusfortner]

I'm using this with my black box API tests to generate JSON schema from each REST call I make, storing it in git, then verifying future rest calls verify against that schema. This is a quick way to detect changes in the API. I've only tested it against my test suite, so there might be more gotchas that this doesn't account for. Updates or feedback on an improved approach would be appreciated.

[coveralls]

Coverage decreased (-88.2%) to 10.728% when pulling b162797 on titusfortner:schema into aa6939d on brooklynDev:master.

[coveralls]

Coverage decreased (-88.2%) to 10.728% when pulling a195978 on titusfortner:schema into aa6939d on brooklynDev:master.

[coveralls]

Coverage decreased (-88.2%) to 10.728% when pulling 8d3ec09 on titusfortner:schema into aa6939d on brooklynDev:master.

[coveralls]

Coverage decreased (-88.2%) to 10.728% when pulling 12dbe57 on titusfortner:schema into aa6939d on brooklynDev:master.

[coveralls]

Coverage decreased (-88.08%) to 10.853% when pulling 5cdb800 on titusfortner:schema into aa6939d on brooklynDev:master.