fixed error in IE9 when select contains optgroup, see http://social.msdn.microsoft.com/Forums/is/iewebdevelopment/thread/2ab12546-7bb4-41b6-8d36-442cc0ecb153

when invoking select.remove(..) in IE9 and the select contains optgroup
element, select.remove(..) will throw exception. Solution - catch
exception and remove element using ordinary dom manipulation
fixed code for removing option element in IE9, previous solution didnt work when select contained optgroup..
Merge pull request #268 from kaililleby/master

Thanks !