Allow larger file uploads

Adjust nginx config to allow larger file uploads so speakers can
upload their slides and other files.
add pycon staging to load balancer
version bump
firewall the pycon servers to disallow direct access
set client_max_body_size for the upstream location only
version bump
Merge branch 'master' into pycon-larger-uploads

Conflicts:
	cookbooks/pycon-2014/metadata.rb
Adding XML packages for lxml/BeautifulSoup import code
Merge pull request #36 from revsys/master

Adding XML packages for lxml/BeautifulSoup import code
Update Application Cookbooks
Use relative paths

The Hardcoded path to /srv/speed.pypy.org/releases/xxxx means that
we inadvertingly update the code for the running instance while
we are deploying the new instance. The window is small but it
means we could get a mismatch.

This change makes the path relative to the settings.py so it always
uses the current revision, and it removes the need for our
forked application_python.
Merge pull request #38 from dstufft/upgrade-applications

Upgrade applications