20120825
========

- New module :mod:`lino.modlib.vat`. 

- Discovered and fixed the following bug in
  :class:`lino.core.actions.ActionRequest`:

    A programmatic request (without HttpRequest) 
    on a table with parameters didn't fill default values 
    into `param_values`.

  This bug was discovered by the following 
  code (in :mod:`lino.modlib.ledger`)::

      for jnl in Journal.objects.all():
          m.add_action(jnl.voucher_type.table_class,
              label=unicode(jnl)+' (%s)' % jnl.id,
              params=dict(master_instance=jnl))


- Another subtile bug fixed:
  :func:`lino.dd.inject_field` now does nothing when it is called for a Model 
  whose `app` is not installed. 
  Discovered by :mod:`lino.modlib.accounts` where it wouldn't be intuitive 
  to require the application developer to check whether `products` 
  is installed before calling `inject_field`.