Fixes #5

Not ready for merging. Here for review. See #5 and https://github.com/yeoman/yo/pull/167. Better ideas are welcome!
Hmm, yeah my regex is weird. It shouldn't do any capturing groups.

What do you think about `/\u001b\[(?:[0-9]{1,3}(?:;[0-9]{1,3})*)?[m|K]/g`?

There's no reason we need to do any capturing at all.

This would change the replace method signature to: `function (match, offset, string)`.