#110 add specific adjustment on shipment cost

[Pierre Gaudin]

It's not possible at this time to add a specific tax value on shipment cost :

For exemple if tax apply on order iten is 5.5 and if you want to apply a 19.6 tax on shipment you can't.

To fixe this, i create a new TaxAuthorityRateType "ADJUSTMENT_TAX" that you can use to define a new TaxAuthorityRateProduct. This tax will be apply only for shipment adjustment at this time.

In the calcul of orderTax process, first we search for a taxe with TaxAuthorityRateProduct type to apply on orderadjustement. If there is no taxe then get the general tax to apply.

[Pierre Gaudin]

patch for head