sequences: faster remove-nth.
sequences.snipped: adding snipped virtual sequences.
hash-sets.numbers: adding number-hashcode version of hash-sets.
hashtables.numbers: adding number-hashcode version of hashtables.
sequences: cleanup shared code between supremum-by and infimum-by.
db.tester: put cpu in sqlite-test-db name.
math.combinatorics: big speedup to combinations.
math.combinatorics: much faster permutations, cleanup combinations code.
math.combinatorics: cleanup stack effects to be more descriptive.
math.combinatorics: minor fix to reduce-combinations stack effect.
io.files.info: Add file? and symlink? words.
math.combinatorics: fix map>assoc-combinations (shouldn't have been locals).
io.files.info: Longer names for file-info predicates.
binary-search: faster by specializing on array and vectors.
benchmark.crc32: do more work in the crc32-benchmark.