[Fluxus] rgb & hex colour conversion

[gabor papp]

> here are a pair of functions to convert between rgb and hex colour
> descriptions, eg. "#ffffff" -> (255 255 255). im not sure where they
thanks nik. i needed functions like these in the past. i think these
could be part of fluxus, but it would be easier to use them if they
converted from/to fluxus colour values, e.g. #(1.0 1.0 1.0) instead of
(255 255 255), and use vectors instead of lists. also we should take
care of the alpha value also, so the function could take 3 or 4 element
vectors and #aarrggbb or #rrggbb format strings. or should we use
hexadecimal numbers instead of strings? #xffffff instead of "#ffffff".

best,
gabor