Namespaced events

http://docs.jquery.com/Namespaced_Events

This pull requests allows us to keep the standard events (`open`, `change`, `close`, etc) without having them bubble up and trigger events that were not intended (closing modals, for example).

Using the `[event].select2` syntax, people can still catch the event as `[event]`, but the events are not caught by other plugins, as the namespaces would not match.