Add some way of being able to post process an object read

[nick]

Something like this would be good:

class A(object):
    pass

def pr_A(obj):
    if hasattr(obj, 'prop'):
        del obj.prop

    return obj

pyamf.register_class(A, 'A', post_read=pr_A)

An alias is required for this operation.

[nick]

This ticket has been completed in source:pyamf/branches/gae-key-307. The ClassAlias? can now be subclassed and three new methods have been added: applyAttributes, createInstance, getAttributes all which help greatly to provide fine control for object/instance manipulation.