Add 640x512, 640x256, 320x256, 640x360, 512x192 and 960x540 modes and restored 512x384 mode to VDP

[avalonbits]

@tomm this is the new PR, that replaces the one I accidentally closed

[julianregel]

If the purpose of these additional modes is to provide a better integer scale for modern monitors, then possibly consider adding 960x540 as this is quarter "Full HD" (1920x1080). I'm assuming this would be in 2 colours only (but haven't checked, so maybe 4 colours would fit too?).

[BlastBrothers]

While we're at it... 720x540 would be quarter 1080p at 4:3...

[avalonbits]

I have tested 640x360 (quarter 720p, 16 colors) and 960x540 (quarter 1080p, 2 colors) before and both work well. I've added them both, but you will need vdp-gl 1.0.4 (which I just released) to get the 640x360 resolution.

[avalonbits]

While we're at it... 720x540 would be quarter 1080p at 4:3...

Don' t think there are a lot of 1440x1080p monitors to justify that support. Also, I would need a working modeline for that, which fabgl does not have.

[avalonbits]

Now we have:

• 640x512 with 4, 2 colors
• 640x256 (stretched) with 16, 4 and 2 colors
• 320x256 with 64, 16, 4 and 2 colors
• 640x360 (quarter 720p) with 16, 4 and 2 colors
• 512x384 (quarter 1024x768) with 16, 4 and 2 colors.
• 512x192 (stretched) with 64, 16, 4 and 2 colors
• 960x540 (quarter 1080p) with 2 colors.

Requires vdp-gl 1.0.5 (updated in this PR).

[avalonbits]

@stevesims anything else you see missing here?

[avalonbits]

@stevesims ping. Anything else I need to update here?

[avalonbits]

Should i just close this PR?

[avalonbits]

I would still like to merge this one. Anybody can review?