add redirect_uri, change to image_uri for /client/:id

fixes #30 and fixes #31
Merge pull request #39 from mozilla/get-client-updates

add redirect_uri, change to image_uri for /client/:id
update package.json. fixes #41
default config to prod

- default logging is json format
- pretty is in dev.json and test.json

helps #35
default log level to INFO