metrics should call send rather than add
Merge pull request #14 from antonydenyer/master

Metrics Time should call Send
Always run metric integration tests against localhost ip so they run out of the box.
Added override for statsd port to the metrics config class, and using that in the integration tests.
Added test for prefixes with the metrics helper class.
Reduced timeout from 5 seconds to 2.
Added tests to fully cover the Metrics helper class.

Since it's static I have it setting the internal statsd client to null if you don't set a statsd server name - doesn't change anything, but feels weird doing that for a test, but no other easy way around and didn't want some kind of Reset() method polluting the interface.
Cleaned up Metrics helper class and its integration tests - inlined helper methods, etc.