CAIRO (Reuters) - Outsiders traversed the Sahara's expanses in the imagination long before the first European explorers ventured into the desert's uncharted interior. Now war, banditry and an al Qaeda offshoot threaten tourism and could leave a region bigger than Australia off limits again, wiping out income for its nomadic inhabitants. Author and analyst Eamonn Gearon wandered the Sahara for years, often on the back of a camel, before he wrote "The Sahara: A Cultural History", a book that dispels myriad myths about a place and people long caricatured by clueless foreigners. ...