WhiteCat: other branches merged!

I've merged other two branches within the WhiteCat project and published them on the public available SourceForge repository.

These changes involve the locking mechanism and the role repository. The latter has been refactored in order to keep advantages of the Spring configuration. Spring is taking more and more space within WhiteCat, as demonstrated from the removal of the old Configuration class.

The locking mechanism has been completely rewritten. The locking is a mechanism that allows the role developer to mark (annotate) a proxy method in order to avoid its execution while the proxy itself is undergoing role manipulation. This is useful in order to avoid critical races on proxy mutators. The locking is managed by the ProxyStorage, that is an object that keeps track of all available proxy instances and their manipulation status, providing support for getting the last-updated proxy with a specific proxy identification. The locking mechanism is implemented with an AspectJ aspect that, before the execution of a locked method (i.e., a method with the @Lock annotation), consults the proxy storage in order to see if the proxy is going under manipulation, and in such case can (i) delay the method execution or (ii) avoid the method execution throwing an exception. Each time the role booster starts a role manipulation operation it instruments the proxy storage to lock the proxy, so that the system is aware that the above proxy is going to be manipulated by a proxy. The proxy storage has obtained a "make up" and now stores a wrapper object, called the ProxyStatus, that contains the last manipulated instance of the proxy, some statistics (e.g., how many time it has been manipulated) and a locking object, that is the one the locking mechanism relies on. This means that each proxy has its own locking object, that is used to synchronize Java threads.

Finally, there is a new JUnit test that demonstrates and tests the locking mechanism itself.