Use Spring dependency injection for SecurityServerClient and HttpAuthenticator in Crowd applications

This will make unit-testing these components much easier:

• Crowd Console
• Demo Application
• OpenID Server
• Acegi Connector

For non-Springified components, use constructor injection via singleton factories.

This organisation will allow custom application developers to use the Crowd client libraries either via externally managed singletons through dependency injection (eg. for applications that use IoC already) or via internally managed singleton factories (eg. for applications that don't use IoC).