Fix clouds2d: create own canvas element

The 2D WebGL renderer now creates its own <canvas> overlay inside
the target element, instead of expecting the target to already be a
canvas. This fixes 'canvas.getContext is not a function' when the
target is a <div>.

config.js

@@ -73,7 +73,7 @@
  *                                                        Mon Oct
  */
 window.CONFIG = {
-    debug: 1,
+    debug: 0,
     theme: 'ash',
     units: 'metric',
     renderer: 'clouds2d',  // 'vanta' or 'clouds2d'