Believe it or not, Los Angeles funk outfit War began their musical revolution 50 years ago, churning hit after hit with songs like “Low Rider,” “The World Is A Ghetto,” and a bevy of other songs we know all the lyrics to. A new compilation, “Greatest Hits 2.0,” rounds up all of our favorites into one tidy package, including the classic hug-a-thon song “Why Can’t We Be Friends?” from 1975.