Add simple tcp<=>unix_socket proxy tool.
Add simple tcp<=>unix_socket proxy tool.

This tool will create a tcp to unix socket proxy listening
on an ephemeral port. It is useful for proxying `go tool pprof`
to a cannula enabled server. It is also useful if you are using
an older version of curl that doesn't support --unix-socket (which
was added in 7.40).

retailnext/cannula