For now, there is only the label, type, and active fields. We will need
some field to hold the area on the map, but this requires #4, and
possibly #6, to be finished.
Part of #27.
Had to export and move PublicPage struct to template because i can not
import app from campsites/types: app already imports campsite for the
http handler, and it, in turn, imports the types package for its own
http handler; an import loop.
Also had to replace PublicPage.MustRender with a Setup function because
the page passed down to html/template was the PublicPage struct, not
whatever struct embeds it. I was thinking more of Java inheritance here
rather than struct embedding.
jordi fita mas