* Right now, only already known loaded drivers will be monitored for changes;
their devices aren't republished, though, since that would cause a deadlock
in the node notification mechanism (listeners are called synchronously);
need to offload that the event handling to another thread.
* On changes of (known) driver directories, the device manager will now print
some info to the syslog.
* Fixed republish_driver() I broke recently (would skip every other node), and
moved it to the driver functions section of the devfs.cpp.
* Implemented currently unused unpublish_driver() function that would have to
be called before reloading a driver.
* If a driver is in use when it's updated, we mark it, but we don't do anything
with that info when we could.
* Minor cleanup.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24036 a95241bf-73f2-0310-859d-f6bbb57e9c96