remove references to color

this version doesn't actually work. Let's make them real.

http://www.reddit.com/r/programming/comments/2mwidh/rusts_central_package_repository_is_up/cm8l8yr?context=3
auto merge of #981 : steveklabnik/cargo/remove_color, r=alexcrichton

this version doesn't actually work. Let's make them real.

http://www.reddit.com/r/programming/comments/2mwidh/rusts_central_package_repository_is_up/cm8l8yr?context=3