Rename typeahead.css to custom.css

All of the demo styling is going to move into this CSS file; it isn't
just for typeahead anymore.
Add StateFace icons to the demo
Better styling for demo's `label`
Style the custom typeahead template
Finish adding state taglines
Only try to remove item if it exists

If you hit backspace when no items have been added, it won't throw an
error anymore.
Add separator between typeahead suggestions
Re-style typeahead dropdown

Less bootstrap-ish, more flat.