Modify the datastore tutorial to suit our purposes.

@eerbiceanu:

Modifies the datastore tutorial to use just a place and a note to persist. Follows this:
 https://developers.google.com/appengine/docs/go/gettingstarted/usingdatastore

To test:
  $ links2 http://localhost:8080
to get a text-based browser experience. Add a location and note and refresh to see the recently added note.