First changes to Capfile, config/deploy.rb, and config/deploy/production.rb

Absolutely not complete.
Tweaks in appearance.

Add a favicon. Tune the scaffolds.css.
Handle the case where a Guest or Guest#party is nil.

Suppress display of a nil party in the Guest show and edit views.
Retry #new if GuestsController#create_from_cnetid doesn’t turn up a person.