Add python module tryton_pos #5519

Added python module tryton_pos
  * RPC method pos_add_product to add product to sale.
  * anonymous_customer required field in sale.shop
  * sale.sale default_party as anonymous_customer.
  * Manage shipment from warehouse accordingly.
Merge pull request #1 from tarunbhardwaj/develop

Add python module tryton_pos #5519