CC-2068:Now playing should use Title/Creator, not Song/Artist

- fixed
- removed some unnecessary code.

airtime_mvc/public/js/airtime/nowplaying/nowplayingdatagrid.js

@@ -64,8 +64,8 @@ var columns = [{"sTitle": "type", "bVisible":false},
     {"sTitle":"Start"},
     {"sTitle":"End"},
     {"sTitle":"Duration"},
-    {"sTitle":"Song"},
-    {"sTitle":"Artist"},
+    {"sTitle":"Title"},
+    {"sTitle":"Creator"},
     {"sTitle":"Album"},
     {"sTitle":"Playlist"},
     {"sTitle":"Show"},