While our Saturday Cinema Summary does an admirable job of rounding up the week's new releases, London's celluloid attractions run deeper than the local multiplex's offerings. From retrospectives of filmmaking greats, to cult classics introduced by obsessive cinephiles, each week we'll offer a preview of the forgotten films and rare screenings worthy of your attention. Wednesday: 4 Months, 3 Weeks, 2 Days, the stark Romanian film that snatched the Palme d'Or at Cannes last......