[MRG]
[ADD] Module to adapt the standard OpenERP report to cost_price field
[IMP] Make the cost_price a stored field
[IMP] Adapt the product_price_history module to hide value information and provide a view for inventory valuation
[IMP] Strongly improve the computation of BoM cost_price by including all bom trees in the update
[ADD] New module to make the glue between product_price_history and product_cost_incl_bom
[ADD] Strong tests cases