IE 9 support.

[naz]

IE 9 doesn't work properly (no content is loaded) and gives ember errors.

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; BRI/2)
Timestamp: Wed, 25 Apr 2012 09:34:36 UTC

Message: Unable to get value of the property 'extend': object is null or undefined
Line: 13
Char: 3111
Code: 0
URI: http://petelepage.com/webapp-codelab/finalproject/js/libs/ember-0.9.5.min.js