[Coco] WIP XRoar composite video support

[Allen Huffman]

> On Mar 28, 2023, at 9:22 AM, Ciaran Anscomb via Coco <coco at maltedmedia.com> wrote:
> 
> I've written up the work in progress here:
> 
> https://www.6809.org.uk/xroar/cvbs.shtml
> 
> tl;dr: XRoar with a "TV Options" dialog that lets you play with various
> aspects of composite video encode/decode, both NTSC and PAL.

Exciting work. Though I am sad, being a macOS user.