Fix leanderseige#2 - workaround for DOM method remove() which is not …

…supported by IE11

iiif2pdf.js

@@ -428,7 +428,9 @@ function iiif2pdf(config) {
     var ctx = canvas.getContext("2d")
     ctx.drawImage(img,0,0)
     var retimg = canvas.toDataURL('image/jpeg',q)
-    canvas.remove()
+    if (canvas.parentNode != null) {
+      canvas.parentNode.removeChild(canvas);
+    }
     return retimg
   }