Strip mIRC formatting characters

[Sanqui]

Messages from the IRC side with colors show up as numbers on the Discord side.

Could probably just use this: https://www.npmjs.com/package/irc-colors

[ekmartin]

Yep! #166 fixed this, but the author wasn't interested in adding irc-colors for it - which I think is a better solution. Feel free to send a PR if you have time!