Use of with_init with inhitence fails.

[tomprince]

Trying to use with_init in both a base class and a derived class fails. It appears that the generated base class' __init__ is getting called twice. It looks like this is due to a confusion with both classes trying to control __original_init__.

from characteristic import attributes

@attributes(["base"])
def Base(Exception):
    pass

@attributes(["derived"])
def Derived(Base):
    pass

Derived(base="base", derived="dervied")

fails with

Traceback (most recent call last):
  File "test.py", line 11, in <module>
    Derived(base="base", derived="dervied")
TypeError: Derived() got an unexpected keyword argument 'base