Prevented Double submission. Also fixed "Cart marked as DONE" on server cart

- Disabled checkout/purchase button on submit
- Caught "Cart marked as DONE" error via server cart and force clear it before resubmitting cart.
- Cleared Server cart only when order was successful.
Loading order from server cart

Removed bug were it was possible for order details to be wrong on the processed cart page.
Added error message for signout
Moved signin login into profile service
added RememberURL and RequireSignin

- Every URL gets saved when going to it (in case of signin)

- every URL gets checked if it requires login access (based on URL).
Added signin text on checkout button if user is not signed in.
small cleanup