Export catalog to magento #2008 fixes #68

Export products from openerp to magento.

All the products selected for export will be exported to a category, attribute
set chosen by the user from a wizard. The exported products will always be
exported as simple products as other product types need attribute management
which better be left to magento. Other required details like weight, tax class
etc will be hardcoded to some default values which can later be configured on
magento itself.