fix vulnerable ZeroClipboard flash

example: http://localhost:3000/assets/ZeroClipboard10.swf?id=\%22))}catch(e){alert(/Xss/.source);}//&width=500&height=500

  ZeroClipboard10.swf is vulnerable to XSS, switch to latest swf version from https://github.com/jonrohan/ZeroClipboard/blob/master/ZeroClipboard.swf

can you please release and upload a new gem too?