doh...
this happens when you draft some quite intricate logic and then
get sidelined with other tasks for several years. Mind me, I didn't
even recall that I had treated this whole issue and created
a clean-up thread.
A full fledged implementation would have a real lifecycle and
thus detect the re-entrance; but since none of the components
to be managed by the OutputDirector is even remotely planned
or even coded, the functions were just drafted as stubs.
Which caused us happily to create yet another clean-up thread
whenever the subsystem-runner signalled "please shut down".
lib::Depend<TY> works as drop-in replacement for lib::Singleton<TY>
This changeset removes the convoluted special cases like
SingletonSub and MockInjector.
