modified:   tw2/jqplugins/jqgrid/widgets/sqla.py
  RobertSudwarts <robert[dot]sudwarts@gmail.com>

`datetime.date` objects caused `request` to puke with a
'not JSON serializable' error. Hence (line 144):

-- if isinstance(data, datetime.datetime):
++ if isinstance(data, (datetime.datetime, datetime.date)):