Update Turbolinks, load additional assets only on request, fix JS

Signed-off-by: Sebastian Serth <Sebastian.Serth@student.hpi.de>

app/assets/javascripts/editor/turtle.js

@@ -0,0 +1,48 @@
+CodeOceanEditorTurtle = {
+  turtlecanvas: null,
+  turtlescreen: null,
+  resetTurtle: true,
+
+  initTurtle: function () {
+    if (this.resetTurtle) {
+      this.resetTurtle = false;
+      this.turtlecanvas = $('#turtlecanvas');
+      this.turtlescreen = new Turtle(this.websocket, this.turtlecanvas);
+    }
+  },
+
+  cleanUpTurtle: function() {
+    this.resetTurtle = true;
+  },
+
+  handleTurtleCommand: function (msg) {
+    this.initTurtle();
+    this.showCanvas();
+    if (msg.action in this.turtlescreen) {
+      var result = this.turtlescreen[msg.action].apply(this.turtlescreen, msg.args);
+      this.websocket.send(JSON.stringify({cmd: 'result', 'result': result}));
+    } else {
+      this.websocket.send(JSON.stringify({cmd: 'exception', exception: 'AttributeError', message: msg.action}));
+    }
+    this.websocket.flush();
+  },
+
+  handleTurtlebatchCommand: function (msg) {
+    this.initTurtle();
+    this.showCanvas();
+    for (var i = 0; i < msg.batch.length; i++) {
+      var cmd = msg.batch[i];
+      this.turtlescreen[cmd[0]].apply(this.turtlescreen, cmd[1]);
+    }
+  },
+
+  showCanvas: function () {
+    if ($('#turtlediv').isPresent()
+        && this.turtlecanvas.hasClass('hidden')) {
+      // initialize two-column layout
+      $('#output-col1').addClass('col-lg-7 col-md-7 two-column');
+      this.turtlecanvas.removeClass('hidden');
+    }
+  }
+
+};