Deal with API errors

* updated middleman to pass errors back
* more consistently use cb(err, data) convention
* deal with 503 errors (Heroku down)
Fix passing data through as response, and not as error
hard code middleman version (also ^ doesnt work on Node 0.8
lock version numbers
shrinkwrap
Merge branch 'master' into deal-with-api-down
dont need shrinkwrap
Merge pull request #91 from jackfranklin/deal-with-api-down

Deal with API errors