Add tests for udp

- [ ] @sneal

i'd like to get this merged in this week.  we've had a bug where metrics get dropped when trying to send too many at once.  would be good to have this fix in when we switch to druq and start logging a lot of PO metrics
This should [probably be UTF8Encoding](http://msdn.microsoft.com/en-us/library/system.text.encoding.default(v=vs.110).aspx)