cython: 0.25.1 -> 0.25.2

Upstream changelog without issue numbers:

 * Fixes several issues with C++ template deduction.
 * Fixes a issue with bound method type inference.
 * Fixes a bug with cascaded tuple assignment.
 * Fixed or silenced many Clang warnings.
 * Fixes bug with powers of pure real complex numbers.

The full changelog with issue numbers can be found here:

https://github.com/cython/cython/blob/0.25.2/CHANGES.rst

My main reason for updating is because there were test failures on
i686-linux, although version 0.25.2 still has one test that fails.

So if we're on i686-linux and on Python 2 we just fix that one little
doctest.

The test failure has already been reported upstream at:

https://github.com/cython/cython/issues/1548



All of the failing tests (including the latter) had to do with integer
representations in that long integers are suffixed by an L while the
test cases weren't expecting this.

Built successfully on i686-linux and x86_64-linux against Python 2.7 and
Python 3.5.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>