- Replace ->application->io-> with getProvision()->io();

Finish SiteContext Verify: override getSubscriptions() to load http service from platform, get vhost.tpl.php template working, add getProperty() methods to service and subscription.

- Make Application optional in Context constructor so that we can call getContext() statically.

Load Services into Context classes, and load Configuration classes into Services classes. Rewrite Configuration class from Provision_Config. Run write() method on all Configuration classes on `provision verify` command.

Use annotated-command CommandFileDiscovery to lookup all service and service type classes. Use this to ask the user what service they want to add to a server.