[Cython] Python betas delayed again

[Stefan Behnel]

Hi,

just a quick note that the first beta versions of Python 2.6 and 3.0 have been
delayed by another week. They are now expected on June 18. This is mainly due
to stability and build problems caused by last-minute commits.

I would still consider the C API stable by now, as the remaining time is
dedicated to fixing release critical bugs only.

Stefan