replace punctuation (at least sometimes) with whitespace

[cod3licious]

At least for some punctuation signs like .!? it might be better if they are replaced by whitespace instead of an empty string, such that if there is no whitespace between two sentences, the two neighboring words aren't concatenated. Maybe there could be an additional parameter to specify with what punctuation signs are replaced?

[jfilter]

Yes, good idea. Thanks!