Update TODO file with some ideas for improvements in hard link handling
Update TODO file with some ideas for improvements in hard link handling

These ideas may not be very easy to implement, and may not be worth
the performance penalty they might introduce. But that's something that
still needs to be investigated.

ppetr/ncdu,guns/ncdu,piyo/ncdu,guns/ncdu,ppetr/ncdu,rofl0r/ncdu,guns/ncdu,rofl0r/ncdu,sunny256/ncdu,ppetr/ncdu,FauxFaux/ncdu,gitkaste/ncdu,sunny256/ncdu,gitkaste/ncdu,FauxFaux/ncdu