Replace removeExpression() and setExpression() use - fixes IE8,IE9,IE10 bugs

* removeExpression() and setExpression() are not supported in IE8, IE9, IE10 
* This was causing simplemodal plugin not to work in IE8, IE9, IE10
* Applied patch that is documented here: http://www.ericmmartin.com/simplemodal-1-4-4-released/#comment-73180
* Remote testing via browserstack of affected IE versions shows fix works