* added method generateMultivaluedMappedValue that returns a list of mapped
  value properties, instead of one single value

ERP5/Document/Resource.py:
* optimized price calculation with options


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@9275 20353a03-c40f-0410-a6d1-a30d3c3de9de