Remove evil getIfExists() method, used by no one.
Remove evil destroyed() method, used in exactly three places -- one of which
is a test. Replace with equally evil instanceExists() method, which is used
EVERYWHERE -- sigh.

and use it for existing LLSomeClass::cleanupClass() calls.
This logs the fact of making the call, as well as making it.

restore the ll[io]fstream because we need them as wrappers on Windows for wide char paths; on other platforms they are now just typedefs to the std classes