WASHINGTON (Reuters) – President Barack Obama appeared on Tuesday to have persuaded his Egyptian counterpart, Hosni Mubarak, to take a middle course of promising to step aside later this year. It was unclear if that would satisfy the hundreds of thousands of protesters who gathered across Egypt to call on Mubarak to immediately relinquish power. After days of putting pressure on Mubarak while seeking to avoid unleashing instability in the longtime U.S. ally and most populous Arab nation, Obama sent an envoy to privately urge the Egyptian president to prepare for a transition in power. Hours later, Mubarak said in...