Add a utility script to dump SPR files with color palettes that contain non-zero alpha values

[rdw-software]

All the available evidence suggests that these should be discarded. But it might be interesting to see which files warrant a second look.

The implementation is fairly trivial. The decoder can simply flag them while applying palette colors:

RagLite/Core/FileFormats/RagnarokSPR.lua

Lines 117 to 121 in 6344e7d

	if paletteIndex == 0 then
	paletteColor.alpha = 0 -- Should already be zero, but you never know...
	else
	paletteColor.alpha = 255 -- BMP alpha is not supported (except for the background color)
	end

I'd expect the memory overhead to be minimal, but if needed this behavior can be toggled with a debug setting (property).