Issue 9: Adding Coda Hale Metrics directives

- Next iteration
- The goal here is to cover off all of the possibilities
  - success
  - failure
  - rejection
  - exception
- This is accomplished by the addition of 'around' to BasicDirectives (thanks
  Mathias)
- The idea is that you would create a counter (for example) and then specify
  what you want counted.
  - e.g. val counter = metricFactory.counter("counter").countingRejections.countingFailures
- The tests are incomplete - I just realized that I haven't tested the non-case
  (e.g. that a success-only-counter doesn't increment anything on rejections)