Fixes necessary for SDR desktop capture to work correctly and operate compatibly with most imaging software

[Kaldaien]

I have made several changes to fix SDR problems with snipping and pasting.

• "sRGB hacks" have been removed
• RGB captured images will be swizzled to BGR if necessary
• RGBA or BGRA images will have alpha made opaque
• WCG displays running in SDR will no longer take the HDR capture path
• SDR images copied to clipboard will use a normal bitmap for maximum compatibility, since most apps do not understand file path pastes and PNG encoding takes an inordinate amount of time

I also removed the tinted overlay when snipping, since there's a blue rectangle drawn at all times anyway.