* cleanup: go vet and golint run
Various cleanups trickered by go vet and golint.
* Fix tests and lowercase all errors
Lowercase all errors, some tests in kubernetes use errors from
kubernetes which do start with a capital letter.
* Implements tracing in the native gRPC server
* Undo some unnecessary changes
* Properly revert trace/setup.go this time
* Some very very basic tests
* Remove warning for non-Trace middleware
* checkpoint
* Pass context through ServeDNS, enable gRPC tracing
* Fix types and make tracer available to proxy. go fmt
* Fix imports
* Use the DoNotStartTrace option
* Change to SpanFilter from DoNotStartTrace
* Use new name (IncludeSpan)
* Final names
* Add tests; fix possible client/conn leaks in grpc
* go fmt
Adds a middleware to enable tracing with OpenTracing/OpenZipkin.
Enabling tracing will have a large impact on performance so it is
not advisable in production.
