Merge pull request #8 from AlexandreBeaulne/dev

instrumented molderl with statsderl
Merge pull request #9 from AlexandreBeaulne/dev

fixed mess up in initialization of streams/statsd keys
reinstate the old interface for users of molderl app that don't use statsderl
remove the timeout mechanism in the molderl_stream gen_server to solely rely on prodding mechanism
moved from using an external prodder process to erlang:send_after/3 and erlang:cancel_timer/1