Added Spotify tracking. Fixed filters when none given.

config/configuration.js

@@ -22,6 +22,11 @@ const configuration = {
       */
     },
   },
+  spotify: {
+    client_id: null,
+    client_secret: null,
+    redirect_uri: null
+  },
   web: {
     host: null,
     port: null
@@ -43,6 +48,9 @@ if (config.has("scrobble.minimum.duration"))
 if (config.has("scrobble.minimum.percent"))
   configuration.scrobble.minimum.percent = config.get("scrobble.minimum.percent");
 
+if (config.has("spotify"))
+  configuration.spotify = config.get("spotify");
+
 if (config.has("web.host"))
   configuration.web.host = config.get("web.host");
 if (config.has("web.port"))