- Added close handler to be called from comm_close(). Now
all the *CloseAndFree() calls have been changed back to
comm_close() which calls *StateFree, etc.
+ - Fixed comm_select to actually get to select() during background
+ processing.
+ - Fixed rebuild bug which unlinked swap files of already-in-use
+ file numbers.
+ - Added configurable shutdown lifetime (30 sec default)