Adding I18n

Added a config/locales/en.yml (and also a pt-BR.yml) file, moved a lot of hardcoded strings into it and made references to them using Rails's I18n. Also changed a few date's strftime to use I18n.l method.
Yup, Vanity is usable in Sinatra, doesn't have a good example right now though, I'd prefer not to break that compatilibity though.