add base Sample class, taken from API
wat, enable rack test
add instrumentation middleware
add some basic counts
ah, keep rack test with the tests that require it
drop env from metrics prefix

no need for it since we're using different librato accounts
anyways.

plus telex-staging's RACK_ENV is production heh
bring the env back to prefix metrics

this is because we're going to use our production librato account
so it's important that each telex instance instruments on a diff
namespace.

using console_banner here because rack_env is production for both
prod and staging. Ideally I think Pliny should just call this
"deployment" instead, will start a thread on this.
Merge pull request #10 from heroku/pedro-metrics

Base metrics