python scrapy OpenSSL安装不成功?报错

我是python新手，想尝试做爬虫，初步学习后准备安装scrapy。机器是64位，系统为win7，python是python-2.7.9.amd64.msi。scrapy装的是Scrapy-0.24.5.tar.gz

按照教程需要安装依赖包。其他都安装没有问题，import都能通过，但是安装OpenSSL却始终有问题，一开始提醒说 No module named  xxxx，我按照名称去找这些模块下载，但是遇到了 No module named cparser，这个应该是c的东东吧？我下载了以后不知道该怎么办。我想是不是没有装VS2008导致的，就去安装了VS2008。

现在又提醒No module named _cffi_backend，就毫无头绪了。

如果忽略这个错误，直接安装easy_install scrapy也报错（详细在后面）。

继续忽略，我直接输入scrapy startproject tutorial，详细报错在后面，最后一句的意思好像是pkg_resources.py这个包（这个包是装python自己装的）里的一句 raise DistributionNotFound(req)版本有问题？要求cryptography>=0.7？不知道是不是这个意思。但是我现在cryptography的版本号是cryptography-0.8.2.tar.gz啊！

崩溃了，麻烦高手指点！！

openssl安装的是 pyOpenSSL-0.13.1.win-amd64-py2.7.exe
OpenSSL报错详细如下：
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "build\bdist.win-amd64\egg\OpenSSL\__init__.py", line 8, in <module>
  File "build\bdist.win-amd64\egg\OpenSSL\rand.py", line 11, in <module>
  File "build\bdist.win-amd64\egg\OpenSSL\_util.py", line 6, in <module>
  File "C:\Python27\lib\site-packages\cryptography\hazmat\bindings\openssl\bindi
ng.py", line 60, in <module>
    class Binding(object):
  File "C:\Python27\lib\site-packages\cryptography\hazmat\bindings\openssl\bindi
ng.py", line 109, in Binding
    libraries=_get_libraries(sys.platform)
  File "C:\Python27\lib\site-packages\cryptography\hazmat\bindings\utils.py", li
ne 97, in build_ffi_for_binding
    extra_link_args=extra_link_args,
  File "C:\Python27\lib\site-packages\cryptography\hazmat\bindings\utils.py", li
ne 105, in build_ffi
    ffi = FFI()
  File "C:\Python27\lib\site-packages\cffi\api.py", line 56, in __init__
    import _cffi_backend as backend
ImportError: No module named _cffi_backend

scrapy报错如下：
Traceback (most recent call last):
  File "C:\Python27\lib\runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "C:\Python27\lib\runpy.py", line 72, in _run_code
    exec code in run_globals
  File "C:\Python27\Scripts\easy_install.exe\__main__.py", line 5, in <module>
  File "C:\Python27\lib\site-packages\setuptools\__init__.py", line 11, in <modu
le>
    from setuptools.extension import Extension
  File "C:\Python27\lib\site-packages\setuptools\extension.py", line 8, in <modu
le>
    from .dist import _get_unpatched
  File "C:\Python27\lib\site-packages\setuptools\dist.py", line 21, in <module>
    packaging = pkg_resources.packaging
AttributeError: 'module' object has no attribute 'packaging'

scrapy startproject tutorial报错：

Traceback (most recent call last):
  File "C:\Python27\Scripts\scrapy-script.py", line 5, in <module>
    from pkg_resources import load_entry_point
  File "C:\Python27\lib\site-packages\pkg_resources.py", line 2880, in <module>
    working_set = WorkingSet._build_master()
  File "C:\Python27\lib\site-packages\pkg_resources.py", line 432, in _build_mas
ter
    ws.require(__requires__)
  File "C:\Python27\lib\site-packages\pkg_resources.py", line 741, in require
    needed = self.resolve(parse_requirements(requirements))
  File "C:\Python27\lib\site-packages\pkg_resources.py", line 626, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: cryptography>=0.7