Adds the features/uri-features test directory, testing sub-uri
deployment. These tests uses script/server since much of this code is
about configuring the server.  They are not run by "rake cucumber", to
run them use "bundle exec rake cucumber features/uri-test".

Tests requires a working app_config.yml setup with pod_url =
"http://localhost:3000/diaspora"

Patches cucumber.yml to always load step definitions from features/**, see
http://thoughtsincomputation.com/posts/cucumber-step-definitions-and-autorequire-hell