colour lib needs reviewers

[Manu via Digitalmars-d]

I think I'm about as happy with my colour lib as I'm going to be.
It really needs reviews.

I added packed-RGB support, including weird micro-float and
shared-exponent formats.
They're important for interacting with any real-time rendering libraries.
There is only one texture format I'm aware of that isn't supported,
and that is u7e3 floats, only available on Xbox360 ;)

Chromatic adaptation functions are in.
I've done a tidy/reorg pass.

I'm not sure what else should be in the scope of this lib.

PR: https://github.com/dlang/phobos/pull/2845
dub: https://code.dlang.org/packages/color
docs: http://dtest.thecybershadow.net/artifact/website-04a64e024cf75be39700bebd3a50d26f6c7bd163-7185c8ec7b15c9e785880cab6d512e6f/web/library-prerelease/std/experimental/color.html

- Manu