Trigger change event on original select when value changes.  Fixes gh-13

This addresses issue #13, where `change` events on the native `select` aren't happening when the value of the dropkick element changes.  Whether the `change` event is wired up before or after dropkick is applied, this just defers to the `select` itself to trigger whatever event handlers have been wired-up.

This still calls the native `change` when the value is changed due to `reset` being called, which makes sense to me (if you want to opt out of `reset`, use the dropkick `change` option instead), but if it shouldn't be called, it can be moved into the `if (!reset)` statement, too.