[FIX] point_of_sale: fix included price

Complement of 5b50284127

The mentioned commit works well when adding a product, but
- changing the quantity
- changing the customer

won't trigger the fix of the included price.

opw-776530

addons/point_of_sale/static/src/js/models.js

@@ -1393,6 +1393,7 @@ exports.Orderline = Backbone.Model.extend({
         // just like in sale.order changing the quantity will recompute the unit price
         if(! keep_price){
             this.set_unit_price(this.product.get_price(this.order.pricelist, this.get_quantity()));
+            this.order.fix_tax_included_price(this);
         }
     },
     // return the quantity of product
@@ -2294,6 +2295,7 @@ exports.Order = Backbone.Model.extend({
         this.pricelist = pricelist;
         _.each(this.get_orderlines(), function (line) {
             line.set_unit_price(line.product.get_price(self.pricelist, line.get_quantity()));
+            self.fix_tax_included_price(line);
         });
         this.trigger('change');
     },

addons/point_of_sale/static/src/js/screens.js

@@ -2080,6 +2080,12 @@ var set_fiscal_position_button = ActionButtonWidget.extend({
             confirm: function (fiscal_position) {
                 var order = self.pos.get_order();
                 order.fiscal_position = fiscal_position;
+                // This will trigger the recomputation of taxes on order lines.
+                // It is necessary to manually do it for the sake of consistency
+                // with what happens when changing a customer. 
+                _.each(order.orderlines.models, function (line) {
+                    line.set_quantity(line.quantity);
+                });
                 order.trigger('change');
             },
             is_selected: function (fiscal_position) {
@@ -2188,4 +2194,3 @@ return {
 };
 
 });
-