Fixed a bug where SmallWM would enter a loop when relayering a client.

The fix was essentially 'pepper flush_configurenotify calls anywhere they
might be created.' Imprecise, but it doesn't appear to slow anything down
and the problem is fixed.
This reverts commit 7b567 and 5ef4a.

As it turns out, this change creates a situation where there is a 'loop'
of sorts when a client is layered above another. As a result, when I
have more time, I'll work out this particular bug. Until then, I
have reverted to the pre-IconManager setup.