Harmonize module and package name

[bikeshedder]

A lot of Django reusable apps use as package name django-<module_name>. Therefore I would expect django-merchant to contain a module called merchant. Right now it uses billing which drives me nuts for several reasons:

• Upon installing django-merchant one expects a merchant or django_merchant module in the PYTHONPATH; surely not an app called billing.
• Merchant is not about billing. Billing is the process of writing an invoice and sending it to the customer. Merchant does not know about invoices and is in fact just a generic API to payment providers. Quoting Wikipedia: "Billing may refer to: The process of sending an invoice to customers for goods or services (...)"
• I am involved in a project which does accounting, billing, and has apps named like that. Right now I would need to maintain a fork of django-merchant to get around this name clash. Right now Django 1.6 does not check if there is more than one app with the same app label installed, but Django 1.7 will check this and bail out with an error. I know this is just bad luck and might happen with any other package I might want to use in the future. I just want to explain the reason behind creating this issue.

Please rename the module to merchant so it does not confuse new users expecting a merchant or django_merchant module in their PYTHONPATH and stop using the term "billing" in a wrong way.

I might be true to my name, but this really bugged me when I first had a look at django-merchant and was wondering why there is no merchant directory in the sources.

[tuxcanfly]

@bikeshedder not bike shedding at all. I agree and I think the only reason is backward compatibility which maybe handled using a deprecation warning and symlink for an easier transition.