[A volunteer gives away goods to stranded refugees and migrants, most of them Afghans, who find shelter on Victoria Square in Athens]By Lefteris Papadimas IDOMENI, Greece (Reuters) - Each day, Demetrios Zois buys two loaves of bread. One is for his family, and one for whoever comes knocking on his door. In the past year, there have been plenty of unexpected visitors. He is among 100 mainly elderly people living in Greece's border community of Idomeni, which has become the focal point of a growing migrant crisis that is proving too big for the country to handle. Around 30,000 migrants and refugees were stranded in Greece on Thursday, with just over a third of them at Idomeni, waiting for the border with Macedonia to open. ...