Repaired -W option

https://github.com/udoprog/c10t/commit/233149472569a73c1a4ad7204f85590e90ad85e1 changed the color value range from values between 0.0f and 255.0f to values between 0.0f and 1.0f. Casting these values to int will thus only create 0 and 1. This patch recalculates the original int values so they can be saved in a human readable/editable way.