I've just read about IRC protocol. It turns out that there's no standard defined for the colored messages. Although, there are clients that support colors, e.g. mIRC.
They include a
warning on their website:
Please keep in mind, many IRC channels disallow the use of colors, and even in #Beginner, we ask that our newcomers, ops, and voices, keep the color usage to a minimum so that we don't confuse the newcomers too much. We should also remember that those clients without color capabilities (some Linux clients, for instance) will see all our color codes and numbers, and the resulting text is almost impossible to read.
So, I'm not sure, if I'm going to add a support for IRC colors. If yes, then it's going to be optional.