[Cython] failing memory view tests in Python 2.4/5

[Stefan Behnel]

Hi,

I've fixed some of the errors that current block the tests. The remaining
failures in the memory view tests exist in both Py2.4 and 2.5, which hints
at a problem with the buffer support in numpy.pxd.

https://sage.math.washington.edu:8091/hudson/job/cython-devel-tests/BACKEND=c,PYVERSION=py25-ext/504/testReport/

The memslice test failure is annoying. It looks like slice() fails to
properly deep-copy in Py2.[45]. I don't know if we can do anything about
this, seems more like a CPython bug. Deep copying is used to split function
definitions for fused types and I guess slice objects are used in
combination with the memory slices. So both don't currently work together
in Py2.[45].

I'd like to release a 0.17 alpha soon, so please get these sorted out in
one way or another ASAP. I'm also fine with declaring these features
unusable in older Python releases if we can't fix them, but it would
obviously be better to get them working.

Stefan