Standard GUI framework inspired by Qt

[karl via Digitalmars-d]

I'm unsure of the "gamma" space, Adobe should be enough to cover 
things (the curve is practically identical). Still, they are 
different at 0xA7 and 0xBE, so maybe useful for some files. GPUs 
and every non-specialized monitor only do sRGB<->linear.
So, all's good with that pull request, just "gamma" might be 
useless and confusing.