Feature request: allow counting blank space at end of last line in stri_wrap()

[rossellhayes]

c2dd9be refactored the dynamic algorithm used by stri_wrap() to not count blank space at the end of the last line in a string. It would be great if there could be an option to re-enable counting the blank space, so one could create a string where each line, including the last, is as close to even as possible.