aggregates/:check_name age filter parameter

---
      Sensu aggregates are "lazy", as they have no concept of "complete".

      This commit adds the age filter parameter, making it easier to grab
      a recent & most likely "complete" aggregate.

      The age parameter is intended to be used in combination with limit.

      eg. aggregate/redis_stunnel?limit=1&age=20
      ["1361428740"]

      This is a MoPub sponsored feature!

      - /info "health" has been replaced by "rabbitmq" & "redis" "connected"
      - The health filter has been removed