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
Merge branch 'master' into pycon-settings-changes
Add deploy-specific config to gunicorn environment