When IO manager has nothing todo

It runs on its own thread, soon. If no watch on rectangle has been called, it should sleep, and be woken by a watch call. The alternative is that is wakes once a second and checks for mouse activity for no apparent reason.

The console can run without xchars or io manager. If is start IO manager with no xchars, IO manager could try and watch the default system shell, for not much reason. IO manager is not going to attempt a Put String x y; to the system shell, the shell is xterm, not our thing.

Not of this is running, yet, I am still stepping through he paths in a test rig, using console loop.  But it bringsd up the issue of dependence, xchars has to be loaded, generally; and I am not happy that xchars may not hve its own symbol table, but I am not happy to maintain two copies. We would like xchars to come up independent of anything but xcb.

My way out, make the loadable objects linkable at compile time, xchars can use its own copy of the system symbol table. I becomes an independent loadable and I maintain only one copy, and address space and memory wasted; sounds OK to me, but for one thing.  I am accepting complexity at compile time, multiple options heading toward make complexity.