Added arrayDivisible method, to return array with factors removed

Input: a number that defines the range for an array
Output: an array with numbers that are not factors of each other

Steps:
 1) converts the range to an array
 2) checks all elements of the array to see if a number is a factor of another
 3) uses the factor? method to do this
 4) only checks if a smaller number is a factor of a larger number
 5) removes duplicates and sorts the array