Add PHP and ext-intl requirements to composer.json
Support PHP's built-in web server
Upgrade tmhoauth library

This adds a direct dependency on tmhoauth and removes the old Silex provider dependency (the provider is simple enough to implement internally).
Support Twitter API v1.1

Twitter's API now requires user authentication in addition to a consumer key/secret, so add those to the configuration example.
Remove trailing whitespace
Add debug and Google Analytics options to example configuration
Use system temporary directory for HTTP and Twig caches
Actually enable HTTP caching