Presently spawns operations in separate thread to ease clr_read/wake handling.
Seems to perform reasonable well...

hint. The 2.3 consumer needs it for delta-syncrepl.

optimal place yet) to simply event management.  Needs testing.
Place revent clear calls immediately upon handling of event
(before any work).
Misc. other cleanup

fix previous commit (modifyTimestamp didn't get appended to the list); add opattrs to back-monitor mods

track down the infinite loop problem at some point. Probably not backend
dependent.

use inet_ntoa_b(3) instead.