Ticket #14 (new defect)

When calling methods on objects that were defined in a superclass, the child class is used for the node's class_name rather than the class where the method was defined.

Example:

class A(object):
    def __init__(self):
        pass

class B(A):
    def __init__(self):
        A(self)

Will result in two nodes, both with class B rather than one of each. I've attached a patch to fix this