usage: bouncy FILE PORT

Create a routes FILE like this:

  {
    "beep.example.com" : 8000,
    "boop.example.com" : 8001
  }

Then point the `bouncy` command at this `routes.json` file and give it
a port to listen on: 

  bouncy routes.json 80

The `routes.json` file should just map host names to host/port combos. Use a
colon-separated string to specify a host and port in a route.

Use `""` for the host as a default route.

You can optionally specify a listen address as the third parameter or with
`--address`. It defaults to `0.0.0.0`. Specify `::` to listen on both IPv4 and
IPv6 addresses.