Solution to Problem 3.3 / Implementation of Algorithm 3.2
Sorts list of strings in lexicographic order via Mergesort
Author: Ryan McIntyre

Input is given on the command line as a space-separated
list of strings. Only supports A-Z and a-z, but the
alphabet used is arbitrary and can easily be exchanged.

Output is the sorted list of (valid) inputs, along with
the list of invalid inputs (i.e., those with unsupported
characters, if applicable).
