Different solution for setting height on iframes

Solves issue in #67 

Previous solution for setting actual height of demo iframes didn't work proberly for some cases since in Chrome (and other browsers) onload event in iframes does not consider attachements (external styles). See: http://www.atalasoft.com/cs/blogs/jake/archive/2009/06/18/events-to-expect-when-dynamically-loading-iframes-in-javascript.aspx

Therfore I implemented a solution which triggers the resize event from within the iframe which works quite well for me.