It's especially crappy since it doesn't actually do much/any error
handling.

Use:
$ sky/tools/skydb start out/Debug \
  'sky/examples/terminal/index.sky?url=mojo:netcat?host=localhost%26port=80'

(Note: We don't have a resolver yet, so the host either has to be
"localhost" or an IPv4 address in the form N1.N2.N3.N4.)

R=erg@chromium.org

Review URL: https://codereview.chromium.org/1032743002