doc/comment
spelling and grammar
add soft dependency on string-utils.el
only autoload, because string-utils depends on list-utils
add some custom hash-table-tests
numeric comparison
case-folded-string comparison
whitespace-agnostic-string comparison
add function list-utils-and
add function list-utils-not
add function list-utils-xor
add function list-utils-uniq
add function list-utils-dupes
add function list-utils-singlets
change default comparison to equal