Add support for alternate remote ports.

This is working but needs to be documented before we can merge it in. The new settings are documented, but need to document how one would configure a device to have a remote port in one of two ways:

1. "hostname:port" in the hostname field either in the CSV, XML, or JSON, or SQLite formats (this will break w/ RANCID since it's already colon-separated).

2. In XML, JSON, or SQLite formats, you may specify a "nodePort" attribute with a numeric port value.