so the generated c files don't depend on the version of python used to run Cython

slots for new pyton versions are not emitted
for older versions. This stops compiler warnings.

The issue here (as pointed out by Thomas Hunger) is that once the CClass
body gets executed the class is already constructed, and its methods
are actual methods not functions (as in Python).

The CClassScope now returns a utility function on lookup of "classmethod"
that creates a class method out of a method (rather than out of a function).
When added to the type dictionary, the result is exactly the same as setting
the METH_CLASS flag.

a direct change of a classes tp_dict instead
of SetAttr if assignment code is executed in
a class body.
To tell the code generator that we have a class
entry, entry has a new attribute "is_member".

because the class-body code is exectuted at module-init time.

use 'with GIL' instead of 'withGIL' to avoid introducing a non-Python keyword and to support later extension for other contexts

This is so mutating inplace operations can be detected safely.

avoid argument parsing (via meth_o, meth_noargs) for non-python-object arguments, upgrade version number to 0.9.6.4

compiles and runs SAGE fine

previous patch was just for classes

Emulates behavior of

from <module> import *

For some reason, it actually makes it slower in some of the most common cases (now commented out). Why? It does help in others.