By Renee Maltezou and Lefteris Papadimas ATHENS (Reuters) - Alexis Tsipras said on Monday he would revive Greece's banks and its crippled economy, while demanding debt relief from creditors in his "first big battle" following an unexpectedly clear election victory that returned him to office as prime minister. Preparing to be sworn in for a second term, he set those priorities at the top of a dauntingly long "to do" list that also includes implementing austerity polices and dealing with waves of migrants landing on Greek shores. ...