Added generators and python shebang, not tested

I saw a place where you could've used some generators instead of appending to lists, so I added that.

I also added the shebang (#!/usr/bin/python) to execute ./AnimeFormatter on the command line.

NOTE THAT I HAVEN'T TESTED THIS RIGOROUSLY YET because I don't have any folders with many anime files. With that said, you really don't have to merge this pull request.

PS: If you want to parse command line arguments, I'd suggest looking into argparse. And then create a dependencies file, in case someone hadn't installed argparse yet.