Provides the function "prime?" which takes a number N and the number of times to test it K and returns whether the number N is (probably) prime. The probability of its truth is (1 - 1 / (4^K)).

Given an integer x, The number of tests to perform k, and a random number generator rng, which takes a number and returns a number between 0 and the given number. NOTE: the default rng is random, which takes as its maximum value 4294967087.