Millions of widows around the world are left destitute after being robbed of their inheritance, while others are enslaved by their in-laws, accused of witchcraft or forced to undergo abusive sexual rituals, research shows. The crushing poverty and persecution faced by widows worldwide is outlined in a major report on widowhood which will be presented to U.N. Secretary General Ban Ki-moon on Friday. "Widows have been suffering in silence for centu…