Graphite WIP

Graphite end point has been beaten back into shape.  Added test coverage.

Changed config to allow for infinite Graphite listeners... might be something we need to limit at some point.

would love feedback!
If nothing else, I might have changed the function signature to something like this:
```
func (g Graphite) TCPAddr(net* TCPAddr default_if_not_set) *net.TCPAddr
```
What do think? I think this is clearer to the next guy?