closes #1274. turns out an earlier fix for this was lost somehow, i just put it back in

Author: Lauren McCarthy

lib/addons/p5.dom.js

@@ -1,4 +1,4 @@
-/*! p5.dom.js v0.2.8 February 4, 2016 */
+/*! p5.dom.js v0.2.9 March 3, 2016 */
 /**
  * <p>The web is much more than just canvas and p5.dom makes it easy to interact
  * with other HTML5 objects, including text, hyperlink, image, input, video,
@@ -1694,9 +1694,9 @@
       this.drawingContext = this.canvas.getContext('2d');
     }
     if (this.loadedmetadata) { // wait for metadata for w/h
-      if (this.canvas.width !== this.elt.width) {
-        this.canvas.width = this.elt.width;
-        this.canvas.height = this.elt.height;
+      if (this.canvas.width !== this.elt.videoWidth) {
+        this.canvas.width = this.elt.videoWidth;
+        this.canvas.height = this.elt.videoHeight;
         this.width = this.canvas.width;
         this.height = this.canvas.height;
       }