20120809
========


- New module :mod:`lino.utils.quantities` and 
  new implementation for 
  :class:`dd.QuantityField <lino.core.fields.QuantityField>`.
  
  No longer a subclass of DecimalField
  whose value is a `decimals.Decimal`, 
  but a CharField whose values are instances 
  of :class:`Quantity <lino.utils.quantities.Quantity>`.

- Bug fixed:
  NameError "global name 'IntegrityError' is not defined",
  :srcref:`/lino/ui/extjs3/views.py` in form2obj_and_save, line 279