insert (require ...) to (ns ...) macro
use ":refer" instead of ":as" and remove "comb/"
Revert "use ":refer" instead of ":as" and remove "comb/""

This reverts commit 0811f17d36f16d8f2a249058ce8a14fd091467b2.
add :only (combinations permutations) to (:require ...)

make not to be able to use other functions