Add verbose names for multiple Build model fields

- Improve methods for different models

InvenTree/stock/models.py

@@ -426,6 +426,14 @@ class StockItem(MPTTModel):
 
         return self.build_allocation_count() + self.sales_order_allocation_count()
 
+    def unallocated_quantity(self):
+        """
+        Return the quantity of this StockItem which is *not* allocated
+        """
+
+        return max(self.quantity - self.allocation_count(), 0)
+
+
     def can_delete(self):
         """ Can this stock item be deleted? It can NOT be deleted under the following circumstances:
 

InvenTree/stock/serializers.py

@@ -34,6 +34,7 @@ class StockItemSerializerBrief(InvenTreeModelSerializer):
 
     location_name = serializers.CharField(source='location', read_only=True)
     part_name = serializers.CharField(source='part.full_name', read_only=True)
+    quantity = serializers.FloatField()
 
     class Meta:
         model = StockItem