By Nidal al-Mughrabi CAIRO, July 9 (Reuters) - Gazans turned out in large numbers to pay their respects to a senior Palestinian member of Egypt's main aid organisation who set up World Cup screenings in the shattered enclave and was killed by an Israeli air strike on a taxi he was in this week. The strike killed Mohammad al-Waheidi on the eve of the Egypt-Argentina match on Tuesday, along with three other people, including two young passers-by, siblings aged 10 and 8, in the Sabra neighborhood o