ATHENS (Reuters) - Greece's latest round of talks with lenders on an austerity plan was marked by moments of tension as the two sides squabbled over a plan to reform the country's bloated public sector, government officials told Reuters on Thursday. The dispute is the latest challenge facing Prime Minister Antonis Samaras's government, which is struggling to reach agreement both internally and with the troika of European Union, European Central Bank and International Monetary Fund lenders on an unpopular package of spending cuts worth nearly 12 billion euros. ...