CAYO COCO, Cuba (Reuters) - Watch out Cancun and Jamaica. When European charter airlines begin direct flights to this sandy key in the coming weeks, Cuba will be taking another step to recover its position as a premier tourist destination in the Caribbean. Flamingos, iguanas and alligators on a nature reserve are an added attraction for tourists looking to lie on sun-soaked snowy-white beaches and sip daiquiris. Last month, Cuba's communist authorities opened an international airport able to receive wide-bodied jets on Cayo Coco, the largest of a string of hundreds of keys along Cuba's north shore known as Jardines...