The vet checks for some files did not pass for go 1.7. As part of a
preliminary start to making go 1.7 work with this software, go vet
should pass.
Also updated the gogo/protobuf dependency which fixed the code generator
to work with go 1.7 too. Ran `go generate` on the entire repository to
ensure every file was up to date.
With this change remote mapping no longer uses HTTP, as the HTTP ports
exposed by nodes on the cluster are not known cluster wide. The TCP
ports exposed by the cluster service are, so this change uses that
functionality. Each RemoteMapper has its own dedicated connection pool
for each node, and remote mapping TCP connections are in no way coupled
with query TCP connections.