mark v3.withref.json as part of package

setupbase.py

@@ -193,7 +193,7 b' def find_package_data():'
         'IPython.nbconvert' : nbconvert_templates +
             ['tests/files/*.*', 'exporters/tests/files/*.*'],
         'IPython.nbconvert.filters' : ['marked.js'],
-        'IPython.nbformat' : ['tests/*.ipynb']
+        'IPython.nbformat' : ['tests/*.ipynb','v3/v3.withref.json']
     }
     
     return package_data