Problem 41 - Largest Pandigital Prime

* Define function to check if number is prime
* Define function to check if number is pandigital
* Define function to check if number is pandigital and prime
* Copy method from proble 24 (Lexicographic Permutations) to permute pandigital numbers
* Start with pandigital numbers of 7 elements (they're not prime with 8 and 9)
Problem 41 - Update - remove pandigital check

* There is no need to check if number is pandigital as only permutations of ranges are being checked (a pandigital number for sure)