Ability to create sRGB display surface

[allebot]

Originally reported by: korval2

Original Ticket: alleg/feature-requests/45

There needs to be a display option that allows the creation of sRGB windows. sRGB bitmaps wouldn't be a bad idea either, but it's very important for gamma-correction on displays.

[guilt]

I think it's time we supported better displays than 888 RGB.

+1 for HDR support as well.

Perhaps getting a working DCI P3 example may be a step in the right direction

[guilt]

Good monitors are still unaffordable to me, best I can test is a cheap Rec209 on a supposedly lower end HDR TV.