Guardfile: Make RSpec watch templates.
.gitignore: Add metadata.json.
recipes/nginx.rb: Add recipe for nginx.

This is an "empty recipe" commit that establishes the testing
environment and expected dependencies.
recipes/nginx: Install nginx daemon.
recipes/nginx: Install devpi-server site.
Add nginx proxy integration test.
nginx site: Account for configurable server port.
recipes/nginx: Account for nginx dir attribute.

The nginx root directory is configurable by the "nginx/dir" attribute.
Our recipe was blindly assuming that this was always "/etc/nginx".
FEATURES.org: Mark nginx complete.
Merge branch 'feature/expose-with-nginx' into develop
recipes/nginx: Style fixup.
recipes/supervisor: Include devpi::server recipe.
recipes/runit: Include devpi::server recipe.
README: Update for recipe changes.
Merge branch 'feature/rework-recipe-inclusion' into develop