Useage: pprw output_type input_file output_file

This program converts a ppm file of type 3 or 6 into either 3 or 6 (users choice). 

output_type: The ppm type of the output file.
input_file: The name of the input file to covert to another type.
output_file: The name of the output file

Grader - I forgot to include my readme file, hopefully this still counts even though it's a little late.
I also updated my ppm files because I forgot to commit those to git. (I use drop box to keep things updated...)