New sensord

* remove go-curl and gouuid dep
* embrace native go datatypes where possible
* remove ContentLenght and IP Measurement properties for now
* create a true sensord unix utility
  * single check
  * emits to stdout
  * emits to statsd
* use nanoseconds where possible
add a basic README
Merge pull request #20 from canaryio/sensord-updates

New sensord