pyp_classes contains two base classes that are used by PyPedal, the Animal() class
and the Pedigree() class. What most PyPedal routines recognize as a pedigree is
actually just a Python list of Animal() objects. An instance of a Pedigree() object
is a collection of METADATA about a list of Animals(). I know that this is confusing,
and it is going to change by the time that PyPedal 2.0.0 final is released.