Remove inline onclick handlers

Using your plugin in a chrome extension, and chrome forbids inline onclick handlers:

>Refused to execute inline event handler because it violates the following Content Security Policy directive: "script-src 'self' chrome-extension-resource:".

See http://developer.chrome.com/extensions/contentSecurityPolicy.html

I've removed the two instances on onclick from select2. The first instance I swapped out to use your `killEvent` helper and the second one was superfluous since `killEvent` was being called in the handler anyway.