Switched selector to use select2 plugin

@settinghead @donnapep @stulees please review & merge. Thanks.
FYI: try-catch can have performance issues in JavaScript: 
http://stackoverflow.com/a/3217308

So instead of doing try-catch, I'd do something like
```javascript
if (!queryResponse) {
   deferred.reject("No response");
}
else if ... {}
```