Moved _add_or_update method from cart to sale #4366

Added depreciation warning in cart._add_or_update
Add new method to update taxes in sale #4366
Merge pull request #34 from tarunbhardwaj/develop

Moved _add_or_update method from cart to sale #4366
Added refresh taxes to sale line #4366
Merge pull request #35 from tarunbhardwaj/develop

Added refresh taxes to sale line
Merge pull request #33 from prakashpp/develop

Use new route decorator
Only salable products can be added to cart #4488