Fix citybike_payload

By returning next_middleware() at the end instead of response, this
middleware was having no effect.
Merge pull request #19 from APItools/fix-citybike-payload

Fix citybike_payload
Remove add-metrics middleware (dupe of measure-x-ratelimit-remaining)
Merge branch 'master' into middleware-testing
add privacy_spec.lua
response_size_metric_spec