Introduce RGB class
Add RGB#+, #-
Use RGB object in Color class
Introduce HSB class
Add HSB#+, #-
Add error handling to#[]
Add #<=>, #move_to_top
Use HSB class in color object
Add RGB#coerce to make Fixnum#+ accept rgb object
Fix #hsb2rgb
Add alias to_a
Introduce color space mode
Subclassing RGB and HSB to ColorSpace class
Refactoring
Add #-
Introduce NAME class
Use NAME object in Color class
Merge Colorset.[] to .new
Change .new to take options
Set color output mode based on the order
Refactoring
Change: determine next and prev color based on color output mode
Add #info, Fix #dark?