LONDON, Nov 8 (Reuters) – Angolan crude cargoes flew off the shelf this week as refiners mopped up heavy, sweet oil that produces high yields of fuel that will comply with new IMO rules on shipping from January. * Relatively firm refining margins were helping to buoy the market for light, sweet Nigerian * In the Mediterranean, light, sweet grades such as Saharan Blend and Azeri Light were also propped up. Azeri Light in particular has been selling at record highs despite the rec