Commenting fields and constructors

Commenting fields and constructors and makinf fields private. Creating
accessor methods for private fields. Also, some rewriting of method
comments.
New save image class TangleGraphList

This class allows user to select image and save higher quality image to
a file.
Adding Louis Kauffman Tangle Theorems.

New class for Kauffman and Lambroupoulou's theorem on sum of two
rational tangles and the test code.
Adding scale parameter to tangle graphs.

Added scale parameter to tangle graphs allows the user to save higher
quality images of tangle images.
Reorganizing methods and comments.