Printer support

[sh95014]

Describe the bug
Support something like an Epson LX-80 printer.

AppleWin#1017
AppleWin#1026

[sh95014]

work-in-progress branch: https://github.com/sh95014/AppleWin/tree/printer-support

[sh95014]

Branch is looking pretty good now, except that what I’ve built is a serial printer connected to a parallel port, which means you should remove the & 0x7F in ParallelInterface.cpp to pass through all 8 bits for some apps to work. Oops.

Remaining work:

• Write the help text.
• Adopt the instantiation work of the parallel interface card from upstream.
• Wait for upstream to integrate APEL (and figure out a serial printer?). Probably means configuration UI changes.
• Maybe build Epson FX-80 support.
• Support other Imagewriter text font sizes. This means implementing SetFont in MarianiWriter, but there may not be an appropriate font for the “condensed” variants of Imagewriter, and I’m not sure many actual programs even use these printer fonts at all since they’re brand-specific. Not inclined to bother with. (Edit: turns out Epson FX-80 is Pica by default so had to do it anyway. The switch may just work, but I didn’t actually test it.)
• Maybe have the printer page scroll off the top when we move to the next page. I couldn’t easily get AppKit view animations to work so I gave up quickly. Also not sure it’ll look right while a new page slides down in the thumbnails list.
• Automatically pop-up the printer window. We can detect when things are being printed, but then if the user closes it explicitly we shouldn’t pop it right back up. This means we would need to understand the concept of a print session, which doesn’t really exist.
• Figure out why there the FX-80 emulation seem to have issues with PrintShop (some aliasing possibly related to the macOS writer being wedded to 72dpi), Newsroom (vertical gaps, probably because it's printing at 60 dpi to a 72 dpi writer), and Dazzle Draw (horizontal gaps, not sure why).