ENHANCEMENT: can now build empty IpRanges.
REFACTOR: remove some 'throws' clause in 'ProtectedAreaNames.java'.
ENHANCEMENT: introduce the interface Address (will later help to enhance firewall rules objects).
ENAHCEMENT: some error messages should be more user-friendly.
BUG: introduce the AWS PLug-In task 'reset-protected-area',in order to solve protected area dependencies issue which may occurred during the protected area deletion.
FEATURE: it is now possible to define Protected Areas as firewall rules's src/dest address.
ENHCANAMENT: extension 'vm' now call reset-protected-area before delete-protected-area (which resolve the protected area dependencies issue).
ENHANCEMENT: AWS Plug-In test case now deal with reset-protected-area.