Widescreen support

[OpenRift412]

Mentioned this on Discord, but just gonna put this here for completeness.

Given the lightly enhanced nature of vanilla conquer, I think it would be nice to have some form of widescreen support, at least at 400p. 480p seems to be a bit more challenging to implement due to the need to somehow extend the sidebar asset to the full height, but I'd say adding an aspect-adaptive widescreen mode that uses the non-square pixel scaling of 400p would be the best way to go about it to start.

[OpenRift412]

Probably not necessary for DOS mode, of course (though it'd be funny to have lol).

[hazelnot]

adding an aspect-adaptive widescreen mode that uses the non-square pixel scaling of 400p would be the best way to go about it to start.

I'd also argue that a square/non-square pixel switch should be added in this case as well, since there are assets in both C&C Gold and especially Red Alert that seem to imply that the Windows versions are designed to be played at 16:10 with square pixels

[giulianobelinassi]

We should get arbitrary resolution support. down to 256x192 all the way up to 4k.