Check that scratch-render and scratch-vm are using the right versions

src/playground/editor.jsx

@@ -1,5 +1,4 @@
-// must be first for progress bar to work
-import './tw-hacky-progress-bar';
+import './tw-imports';
 
 import ReactDOM from 'react-dom';
 import React from 'react';

src/playground/player.jsx

@@ -1,5 +1,4 @@
-// must be first for progress bar to work
-import './tw-hacky-progress-bar';
+import './tw-imports';
 
 import ReactDOM from 'react-dom';
 import React from 'react';

src/playground/tw-imports.js

@@ -0,0 +1,4 @@
+// this should be the first file imported by all entry points
+// the order of these imports does matter
+import './tw-hacky-progress-bar/index.js';
+import './tw-self-check/index.js';

src/playground/tw-self-check/index.js

@@ -0,0 +1,17 @@
+// Check our dependencies to make sure we are using the TurboWarp versions forks.
+// This is a development tool -- users should never see these messages.
+
+/* eslint-disable */
+
+import VirtualMachine from 'scratch-vm';
+import RenderWebGL from 'scratch-render';
+
+if (!VirtualMachine.isTurboWarp) {
+    alert('The installed scratch-vm is not the TurboWarp fork.');
+    console.error('The installed scratch-vm is not the TurboWarp fork.');
+}
+
+if (!RenderWebGL.isTurboWarp) {
+    alert('The installed scratch-render is not the TurboWarp fork.');
+    console.error('The installed scratch-render is not the TurboWarp fork.');
+}