include stats in results for single stand

- The properties of a stand, returned by /stands and /stands/:id
  previously differed. Most bothersome was that the info about latest
  updates wasn't included in the singular endpoing (/stands/:id).
  This fixes that. (The only difference now should be that the
  list endpoing (/stands) still does not return the `updates` array,
  but I'm fine with that for now at least.)

- Note the query in /stands/:id is very similar to that for /stands.
  I'll point the current differences:

  stands/

      ...
      FROM updates GROUP BY "standID"
      ...
      ORDER BY id;

  stands/:id

      ...
      FROM updates WHERE "standID" = ($1) GROUP BY "standID" \

      FROM updates WHERE "standID" = ($1)
      ...
      WHERE stands.id = ($1) LIMIT 1';

  Because in /stands, we need all rows of the stats table, whereas in /stands/:id we can limit by ID.