Rewrite `colortrans`

[jbrubake]

Although likely unintentional, the colortrans source indicates All rights reserved. The script needs rewritten so there is no issue with licensing.

[jbrubake]

See https://gist.github.com/MicahElliott/719710/ and https://github.com/chadj2/bash-ui/blob/master/COLORS.md#xterm-colorspaces