EDWIN WAITA WHEN Danish national Martin Nielsen moved to Kenya to work with a venture capital firm, he quickly switched gears after spotting an opportunity in streaming music and selling downloads. Fast forward eight years and the Kenya-based company he co-founded and now leads, Mdundo, is listed on the Danish stock market and is posting rapid growth in users in the African markets it serves. Africa has been attracting international audio streaming firms like Sweden's Spotify and Apple Music, keen on capitalising on growing internet users and rising demand for legal content. "The market is getting bigger," Nielsen told Reuters.…