Fix ie

On IE11 document.selection is deprecated. They suggest to use "document.getSelection()" instead.
http://msdn.microsoft.com/en-us/library/ie/bg182625(v=vs.85).aspx

So here I check if old style is supported, if not try to use another function.
This fixes https://github.com/SamWM/jQuery-Plugins/issues/62 issue