const fn for Color::from_rgba8

[jeffreyrosenbluth]

It would be nice to have a const version of this so it is possible to create color names in an application.

[RazrFalcon]

Will take a look. Does float operations already const in Rust?

[Woodman3]

emmm,it still not,but i think const fn is stil should be add

[RazrFalcon]

It will be added when I would have time.

[Woodman3]

I have see the source code and find it seem not easy to do it . Because from_rgba use NormalizedF32:new_u8() and this function is also not const. And to make this function constable it may use f32::from::<u8>() but it is also not constable...