Add split-on-whitespace?

[cgay]

It's not super uncommon to want to split a string at whitespace boundaries. Should we add a split-on-whitespace function to complement split-lines? I would suggest the name split-words, but that might get into the territory of "what is a word?", which belongs in a text processing library of some sort.

Prepositions are pretty arbitrary, so I have no idea if split-on-whitespace or split-at-whitespace or something else would be a better name.