Given a string, return true if the input string is a permutation of palindrome or false if it is not. Permutation means that all letters of the string can be used to create a palindrome.
Palindromes are strings that form the same word if it is reversed.
permutation_palindrome?("gikig") == true
permutation_palindrome?("ookvk") == true
permutation_palindrome?("sows") == false
permutation_palindrome?("tami") == false