toggle turbo mode on shift click the green flag

src/containers/green-flag.jsx

@@ -11,18 +11,24 @@ class GreenFlag extends React.Component {
         super(props);
         bindAll(this, [
             'handleClick',
+            'handleKeyDown',
+            'handleKeyUp',
             'onProjectRunStart',
             'onProjectRunStop'
         ]);
-        this.state = {projectRunning: false};
+        this.state = {projectRunning: false, shiftKeyDown: false};
     }
     componentDidMount () {
         this.props.vm.addListener('PROJECT_RUN_START', this.onProjectRunStart);
         this.props.vm.addListener('PROJECT_RUN_STOP', this.onProjectRunStop);
+        document.addEventListener('keydown', this.handleKeyDown);
+        document.addEventListener('keyup', this.handleKeyUp);
     }
     componentWillUnmount () {
         this.props.vm.removeListener('PROJECT_RUN_START', this.onProjectRunStart);
         this.props.vm.removeListener('PROJECT_RUN_STOP', this.onProjectRunStop);
+        document.removeEventListener('keydown', this.handleKeyDown);
+        document.removeEventListener('keyup', this.handleKeyUp);
     }
     onProjectRunStart () {
         this.setState({projectRunning: true});
@@ -30,9 +36,19 @@ class GreenFlag extends React.Component {
     onProjectRunStop () {
         this.setState({projectRunning: false});
     }
+    handleKeyDown (e) {
+        this.setState({shiftKeyDown: e.shiftKey});
+    }
+    handleKeyUp (e) {
+        this.setState({shiftKeyDown: e.shiftKey});
+    }
     handleClick (e) {
         e.preventDefault();
-        this.props.vm.greenFlag();
+        if (this.state.shiftKeyDown) {
+            this.props.vm.setTurboMode(!this.props.vm.runtime.turboMode);
+        } else {
+            this.props.vm.greenFlag();
+        }
     }
     render () {
         const {