added coupon text for clarity and coding standards fixes

Sometimes the coupon code is not always descriptive so to make it more clear as what the discount is for, we should add the "coupon" text.  Or else it will look like this http://cld.wthms.co/YJ5l

After http://cld.wthms.co/gVw1

Coding standard fixes

Fix shipping cost total not updating when using select dropdown method on cart page.

Fix shipping cost total not updating when using select dropdown method on checkout page.