Add a handler to deal with runtime errors.
Add a HealthHandler struct to get at some basic health info. For now, just
response codes. Fix the test to work in this namespace.
Allow the logger to be overriden.
Add some doc.
Add modification header.
Update README. Add missing result code callback.
Allow an endpoint specify its own 'produces' tag. This will override the
default set on the service.
Add the extra produces to the docs.
Add headers for the modified files.