Simplified increment_color method, added more descriptive comment for RDocs for replace_colors method.
Simplified increment_color method, added more descriptive comment for RDocs for
replace_colors method.

iox/gruff,topfunky/gruff,vigetlabs/gruff,topfunky/gruff,jbcden/gruff,jrmhaig/gruff,isozaki/gruff,MentalPower/gruff,house9/gruff,innoq/gruff,philipgiuliani/gruff