[OrderForm] FirstName and Surname fields on Billing Address

[sanderha]

It seems quite normal on webshops to have name fields on both Shipping and Billing addresses. Right now in Silvershop on the standard OrderForm, Billing Address does not have FirstName or Surname fields.

It seems like a good idea in my opinion, to have these 2 fields on both types of addresses.

[bummzack]

I think the Firstname and Lastname should be added everywhere where you add an Address (eg. Shipping and Billing Address).

If there's a logged in Member, we can simply use the values from Member as pre-populated values.