Add Gtk app

gex.json

@@ -1,6 +1,9 @@
 {
   "name": "clapper",
   "files": [
-    "src/player.js"
+    "clapper_src/app.js",
+    "clapper_src/controls.js",
+    "clapper_src/interface.js",
+    "clapper_src/player.js"
   ]
 }