Changing how $app['debug'] is set so that it's available in services.php when setting up providers/services
Cleaning up bootstrap - we always have a Silex application, never just a Pimple container
Adding the Monolog handler and logging on exceptions
Simplifying bootstrapping by always loading the default parameters.

The advantage is that if you *do* need to override some parameters, your parameters.php file only needs to contain the parameters you're overriding, not everything