reddit: add more slots.
sequences.extras: adding supremum-by* and infimum-by* that return indices.
http.client: add quotation stack effects.
math.transforms.fft: small bit of speedup.
combinators.extras: adding 4bi and 4tri.
grouping.extras: having some fun with clumps.
grouping.extras: clean up using.
grouping.extras: adding map-as versions.