Rename length to width.
Add extract methods.
Create Field class/struct.
Use Field struct instead of tuple.
Convert to using ListDict.
Add a comment.
__del__ methods now call super.__del__.
Add __str__ method.
Comment out extradict() and extratodict().
Add superclass of "object".
Add call to super for __init__.
Remove call to super for __del__; it doesn't seem to work with object superclass.