Return references to resources as URIs in triple export

[kba]

Schemo:

Foo
  bar:
    refOne myprefix:Quux

Instance data

_id: "123"
bar: "http://myprefix/api/quux/321"

currently produces

<http://myprefix/api/theClass/123> <http://myprefix/schema/bar> "http://myprefix/api/quux/321"

instead of

<http://myprefix/api/theClass/123> <http://myprefix/schema/bar> <http://myprefix/api/quux/321>