Implement a printer peripheral / interface

[jrsharp]

A "Printer" for PCD-68!

Like other peripherals, this could be realized in both real, actual
hardware, as well as a visual/virtual implementation.
In fact, the web target is a primary application for this -- the thinking being that it would
provide some "bridge" for more traditional web constructs (hyperlinks!) and could be implemented
visually as a stream of annotated text (again, with hyperlinks). The ROM code could provide
a "Send link/page to Printer" function that would send the data to the printer. (Thinking at
the moment this could be a "Markdown Printer" -- that is, aware of markdown formatting, applying
said formatting on virtual (or physical) output medium.