Splendour In The Grass announce killer 2013 line-up with a kick-ass vid! Presented by Village Sounds and Secret Service, Splendour In The Grass 2013 is: Mumford & Sons, Frank Ocean, The National, TV on the Radio, Empire of the Sun, Of Monsters & Men, Klaxons, Bernard Fanning, The Presets, Babyshambles, Flume, Passion Pit, Architecture in…