added pebble-js-app.js in preparation for settings page

src/js/pebble-js-app.js

@@ -0,0 +1,23 @@
+Pebble.addEventListener('ready', function() {
+    console.log('PebbleKit JS ready!');
+});
+
+Pebble.addEventListener('showConfiguration', function() {
+    var url='http://pebble.lastfuture.de/config/supersimple13/';
+    console.log('Showing configuration page: '+url);
+    Pebble.openURL(url);
+});
+
+Pebble.addEventListener('webviewclosed', function(e) {
+    var configData = JSON.parse(decodeURIComponent(e.response));
+    console.log('Configuration page returned: '+JSON.stringify(configData));
+    if (configData.colors) {
+        Pebble.sendAppMessage({
+            colors: configData.colors
+        }, function() {
+            console.log('Send successful!');
+        }, function() {
+            console.log('Send failed!');
+        });
+    }
+});