Just like String.charAt() except for null strings or for strings that are too short, an exception will not be
thrown and instead, a null char will be returned.
If you want to load an image based on where the parent class is loaded, you
don't have access to "this" until after the ImagePanel constructor is done.
Since TextFileIn extends BufferedReader and adds nothing more than a convenient
constructor, all other member functions are identical to BufferedReader.