This change replaces github.com/gogo/protobuf with
google.golang.org/protobuf, except for the code generators.
All proto-encoded structs are now generated from .proto files,
which include ttrpc.Request and ttrpc.Response.
Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>
Set the stage for the example server by including a service definition,
generated code and the protobuild definition file used to generate them.
From here, we can work up to a generated mgrpc server.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
