refactor(ui-bootstrap): add small performance tweak

We only need to find the first menu in the scope of `element`, no need
to keep traversing the DOM after we’ve found it.
feat(doSelect): add doSelect

Add `doSelect` function to `$emit` events when drop down item is chosen
or if `ENTER` key is pressed in the input field. Now it’s possible to
subscribe to events in modules.
version bump to 0.10.0