Machine type `vgaonly` deprecated in DOSBox-Staging

[jspatz]

As of 0.81.0, DOSBox-Staging has deprecated the vgaonly mode, and merged it into its SVGA emulation under svga_paradise, which now supports both 8- and 9-pixel fonts.

However, the DOSBox check in Fontraption is still setting the 'non-vgaonly' flag and disabling the pixel width toggle.

[viler-int10h]

At the moment the program detects DOSBox by checking for the BIOS string. In Staging's bios.cpp I see that the ID text is identical to mainline DOSBox, so that won't be much help in distinguishing them (DOSBox-X doesn't need the 'non-vgaonly' flag either, but -X uses a unique BIOS string, so it's detected and exempted).

It'd probably be easier if Staging had something unique there as well, but it's really sort of an ugly hack... obviously it won't do to start checking for every fork under the sun - hopefully there's a better way to do it by querying the emulated VGA, but I'll have to see whether DOSBox really exposes the difference that way.

For now the workaround is to press Ctrl+Alt+9 within FRAPT, which will override the flag and force-enable the 8/9-dot toggle.