Maze printing formats and new function

[AustinHellerRepo]

I would like to submit a PR that gives the Maze struct a function for printing which accepts in different enum values for ways to be displayed. I wasn't particularly fond of the existing format, so I created another on my local branch. Both could exist together in your repository, distinguished by an enum value of ThinLine and ThickRectangle. Thoughts?

impl Maze {
    fn print(WallFormat wall_format) {
        match (wall_format) {
            ...
        }
    }
}

[ftsell]

As long as there is still a default way of printing the maze via its Debug implementation I'm not opposed to this. So feel free to issue a PR.