Made readme more readable

[bboynton97]

Added some better syntax and linked color references.

The explanations for colors_ignored and colors_not_overwrite are extremely confusing and should be rewritten by someone who knows what it means.

[Qh0stM4N]

@bboynton97 easy colors_ignored : can made transparent image, because pink is ignored. colors_not_overwrite : like don't change red pixels