Update Python 2 and PyPy

* CPython 2.7.9
* PyPy 2.4.0
* meinheld==0.5.7, greenlet==0.4.5
* Fix nginx config.
Cursory searching suggests that you can, but it might be more work than it's worth.

I do not see a good argument for copying the `uwsgi_params` file into `$TROOT` instead of editing `nginx.conf`; they seem to have the same result.