GENEVA (Reuters) - The United Nations refugee agency proposed a six-point plan to European Union heads of state on Friday to resolve the migrant crisis, warning that the situation was quickly deteriorating in Greece where some 30,000 refugees are stuck. The proposal includes setting up EU centres in each state to "take responsibility for all of Europe for registering people and distributing them under an agreed system," UNHCR spokeswoman Melissa Fleming told a briefing in Geneva. U.N. ...