Spotify’s Gimlet Media has tapped Lydia Polgreen, the editor-in-chief of Huffington Post, as its new head of content as the streaming service looks to expand its podcasting lineup. Spotify has made podcasting its focus as it looks to become  the leader in audio, as CEO Daniel Ek has said. The company has spent around $600 million over the past couple of years buying  Gimlet, the maker of such...