CAIRO (Reuters) - The body writing Egypt's new constitution began a session to vote on a final draft on Thursday, a move President Mohamed Mursi's allies in the Muslim Brotherhood hope will help end a crisis prompted by a decree expanding his powers. Mursi is expected to call for national unity in a public address at 7.00 p.m. (1700 GMT) to ease the crisis, which has set off a week of protests and threatens to derail early signs of economic recovery from two years of turmoil. In an interview with Time, Mursi said the majority supported his decree. ...