Fail to update options when they are not strings

https://github.com/hernansartorio/jquery-nice-select/blob/bdbb74f72ca10153f7788a8d9ff8786c23db3f3c/js/jquery.nice-select.js#L126

When the library should update the option for the original selected, it fails to do so if the value is interpreted by js as something other than a string.

For example with the following select.
```

Yes
No

```

Start at js/jquery.nice-select.js around line 126 and reproduce the issue with the provided select containing true and false option values. Trace the update of the original selected option and verify that updates work when a value is interpreted as a non-string. Done means both example options update correctly.

Written by the indexing model from the issue text.