don't try to remove gl2d canvas from gl container in static plots:

etpinard · etpinard · commit 603b8fe5d2c3 · 2016-03-30T17:53:41.000-04:00
- as it doesn't exist after calling scene.toImage.
diff --git a/src/plots/gl2d/scene2d.js b/src/plots/gl2d/scene2d.js
@@ -293,7 +293,7 @@ proto.cameraChanged = function() {
 proto.destroy = function() {
     this.glplot.dispose();
 
-    this.container.removeChild(this.canvas);
+    if(!this.staticPlot) this.container.removeChild(this.canvas);
     this.container.removeChild(this.svgContainer);
     this.container.removeChild(this.mouseContainer);
 
