Adding more #defaultAttrs to with_select mixin (and updating flight component to match)

This is related to https://github.com/twitter/flight/pull/68, and updates a part of the demo app to work with it, since that's what motivated the PR.

I also updated the components/flight source and tests here too (to match what is is #68) so that this is fully functioning and you could see what I was thinking.  I apologize if that's bad PR form, but I wasn't quite sure how to handle it.  If you'd like this presented in a different way just let me know.

Again, thanks for sharing the project!