Create a github pixel identicon.

• Run mix setup to setup project and install dependencies
• In the project directory start an interactive shell iex -S mix and create your image by calling the the Identicon main function and passing the name you want to create an image for Identicon.main("image_name").
• This will create a file in your project directory which you can now view. To open from the terminal, in the project directory enter open image_name.png or view one of the existing images in the project -- open banana.png or open asdf.png