Written by DCist contributor Menachem Wecker. The city’s going to get a little bit wild this Sunday when the National Gallery of Art opens Jungles of Paris, Henri Rousseau’s first retrospective in twenty years. But even if you haven’t seen his work recently in exhibitions, Rousseau is everywhere. You can find references to his work in many children’s book illustrations, like Henry Hikes to Fitchburg or Madeline, in a Joni Mitchell song, and even in…