Favorite ver.4

Feature
=======
EgBӬ[c
Efolding

Structure
=========
  fav4 Dn[cpUG

Efav_t
  iJڪ̷RɡAݨ쪺FNOھ fav_t ͥXӪC
  ̡̭Ao@ level h֭ӬݪOBؿBjuC(favh)

Efav_type_t
  oO[bHUTӪF褧WAONL̵P@تFAK᪺sC
  Τ@ void * ЫVYOAsɥizL type ܼƨӱoTAC

Efav_board_t
  F bid ΤWXɶC

Efav_line_t
  F lid

Efav_folder_t
  F fid ΥiۭqW١C

Efav.c H cast_(board|line|folder)_t() ӱN@ fav_type_t ରTAC

Policy
======
EFקKLתƷhAN@ item qڪ̷RɡAuNL FAVH_FAV
  flag CӨSo flag  item ]Qڪ̷RC

Eڪ̷RAS] FAVH_FAV ơANbYǮɭԡApgJɮ׮ɡAIs
  rebuild_fav MbC

EhݪOҥΪ t A]usb nbrd ̭ASMA˥XB~ŶA
  ҥHbڪ̷RF t A|oӰOȦsb fav ]FAVH_ADM_TAG == 1,
  FAVH_FAV == 0^C
