Incorporate the changes of cython_freeze:
* fix when compiling on Python 3 (Issue #434)
* fix floating point issues on FreeBSD

To get the output of cython_freeze to compile with both Python 2 and
Python 3, I copied the contents of Python-3.1.1/Modules/python.c, with
some slight modifications.  The main issue is that Python 3 uses
wchar_t, while Python 2 uses char.  It also appears that the
Py_FlushLine/PyErr_Clear is not needed in Python 3.

Related to #434: "main() function generated by --embed doesn't compile
in Py3"

The cython_freeze-generated executable exits with code 1 if something
wrong happens, unless a SystemExit exception occurred, in which case it
returns the value passed to sys.exit().  In order to differentiate
between the two cases, change the two example Cython modules to exit(2).

Copy the fix for floating point exceptions on FreeBSD from Python's
Module/python.c.

Python 2 cannot compile with strict aliasing, so the Cython modules
should really be compiled with -fno-strict-aliasing.  See Issue #395.

Add a target (with alias "html") to build README.html from README.txt
using rst2html.  This is not run by default.

The only reason I had a "rst" extension was so that GitHub would pick it
up.

--HG--
rename : Demos/freeze/README.rst => Demos/freeze/README.txt

Add an example of building a --pymain Python interpreter to the README
and to the Makefile.

Add an option to build a regular interpreter, calling Py_Main(), rather
than running the first module as __main__.

Instead of hard-coding the compiler flags and libraries, extract them
from distutils.sysconfig.

I mis-spelled "combinatorics", and I forgot to use the -c flag to gcc.

--HG--
rename : bin/cython_freeze.py => bin/cython_freeze

The files originally had README.rst in the top level and the examples in
the example directory, but now all are in Demos/freeze.

The PyInt conversion functions generate two warnings when compiled under
`gcc -Wall -Wextra`:

1. comparison of unsigned expression < 0 is always false

2. signed and unsigned type in conditional expression

This patch fixes these problems by creating a new temporary variable
`is_unsigned`, which fixes problem 1, and by converting the ternary
return expression into a normal if/else branch, which fixes problem 2.

--HG--
extra : rebase_source : 3512ea980463bae13f30b0d8bd395cabe253e65c

--HG--
extra : rebase_source : 37bb9de5574e1f7b4f288192eaa3c70a2ae350ca

This provides a fast way to check to see the data type of an ndarray.
For example, to check to see if an integer is 64 bits:

    PyArray_TYPE(a) == NPY_UINT64 or PyArray_TYPE(a) == NPY_INT64

--HG--
rename : Cython/Includes/python_string.pxd => Cython/Includes/python_bytes.pxd
rename : Cython/Includes/python_parse.pxd => Cython/Includes/python_getargs.pxd

fix bug 409: use cascaded assignments also for the complete rhs when optimising parallel assignments