[fsnotify] report #3

[Ilya Putsikau]

Done this week:

- Update node path while processing event, first perform direct lookup
for cached path and if it fails try to get full path
- Add rename hook
- Perform full path lookup for fd in addwatch
- Replace full path hash table with inode number hash table.
- Improve path handling in both fnnode and fnevent.
- Remove reference counting from fnwatch, there can be max 2 referencies