Added a missing volatile modifier to an important mutable field that can be accessed by multiple threads -- needed for memory safety on some multiprocessor architectures.
Also fixed some issues with whitelisting the root package (""). You never need to whitelist the root package (non-recursively), since not whitelisting any packages has the same effect as whitelisting the root package -- both whitelisting nothing and whitelisting "" cause all packages to be scanned. However, whitelisting the root package became broken at some point (it caused non-recursive scanning of the root package). This release fixes this so that whitelisting "" works as expected.