Imports of crossdock command

PathSynopsis
github.com/opentracing/opentracing-go
github.com/uber/jaeger-client-goPackage jaeger implements an OpenTracing (http://opentracing.io) Tracer.
github.com/uber/jaeger-client-go/crossdock/client
github.com/uber/jaeger-client-go/crossdock/server
ioPackage io provides basic interfaces to I/O primitives.