- Changed cachemgr stats/objects listing format.

    - Changed cachemgr stats/objects listing format.
        - Added some missing "entry->refcount++"
        - Changed StoreEntry->timestamp to be the last verification time.
          (was the stored-on-disk time).
        - Fixed stuck objects from "304 Not Modified" responses without
          final blank line.
        - Added failure detection to icmpRecv().