fixes checkout issues
1 - updated script.js.cofee to refer id: checkout_form_payment and replaced method .live to .on
2 - Added checkout.js and modified to refer id: checkout_form_payment instead of checkout_form_address
3 - Updated form id to checkout_form_payment to prevent other payment related stuff to work smoothly
4 - Added a check in checkout decorator when use accidently submits the checkout form without payment details
5 - Added a new partial order_details to override spree's partial for one page checkout
6 - Updated Order decorator steps
7 - Before delivery needed for default ship methods