Allow opt-out of cglib proxy

[chrylis]

Due to the interaction between Spring Security and Spring MVC, I need to keep using cglib proxies in my Web application. However, I have a bean whose implementation does not play nicely with cglib, and I would like a mechanism to mark a bean explicitly as "use a JDK proxy".

The @Scope annotation provides an attribute proxyMode and suggests that proxyMode = INTERFACES should get me a JDK proxy, but the ProxyFactory appears to go straight to CglibAopProxy, which throws.