Hook up screen dump code

[inexorabletash]

The "loader" code includes an unused fourth segment that can dump an image of the screen to an ImageWriter II printer hooked up via an SSC in Slot 1. This is never placed in memory but would reside in pages 2/3 where the "invoker" lives.

It looks like this was hooked into the main input logic and would intercept OA-CA-P; possibly it was hacked in for some builds in order to generate screenshots for the manual.

Finding a place to store this and activate it would be pretty cool.

[inexorabletash]

Added a new DA: "Screen Dump". It assumes an SSC in Slot 1 connected to an ImageWriter II printer and dumps the screen. Here's Virtual II after a print:

And here's a more detailed screenshot of the PDF:

Not the most useful thing, but hey - it works.