Fix for IE6 support

[eltonjude]

If inside the dispatchMessage function (legacy mode) you change the width of this.proxyIFrameElement rather than its height, the resize event will fire and things will work.

Hint: http://www.velocityreviews.com/forums/t642052-iframe-resize-events.html

Also, users should include https://github.com/douglascrockford/JSON-js/blob/master/json2.js in their code to make JSON available.

[georges]

Hopefully IE6 is no longer a concern