Working on 2.4.x version

This is a new breaking change.

2.4.x version will declare classes and enumerations as part of
namespaces only.

This means that $def and $enumdef are now absolutely deprecated.

Such change enforces good OOP practices and avoids adding jOOPL objects
in the global scope.

In the other hand, now jOOPL will have named types, since declaring a
class will be performed with a namespace instance "declareClass" method
which requires a name for the class.

Some other improvements have been implemented inside the library code,
mainly a lot of things are now declared using Object.defineProperty
(ECMAScript-5.x) in order to ensure that things declared by jOOPL cannot
be overridden.

Finally, another breaking change "$" (dollar sign) isn't the prefix for
class declaration parameters (same goes for enumerations). Only
$namespace and $manifest keywords remain with this prefix.

2.4.x version goal is getting a cleaner code with jOOPL and a more
classical OOP point of view.