cyclic import bug cont

>>> import soy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/site-packages/soy/__init__.py", line 20, in <module>
    from _core import Screen, Window, \
  File "soy._core.pyx", line 1, in soy._core
  File "soy._datatypes.pxd", line 54, in soy.scenes
  File "soy._core.pxd", line 33, in soy._datatypes
AttributeError: 'module' object has no attribute 'Screen'