BSDDS v0.50 update

Anyone using the Brad Sucks Digital Download Store (BSDDS) should probably upgrade to the new 0.50 release. I haven't been working on it at all but thanks to the power of open source I've been receiving some contributions. These ones are thanks to Geoff Kassel (geoff at kassel dot id dot au):

• made the store easier to customize - including currency settings, messages, and available payment methods
• the store is now in standards-compliant HTML 4.01
• added support for new file formats so that the store can sell e-books
• preliminary support for per-product shipping pricing
• debug code can now be toggled
• logging output can now be customized and toggled
• the admin login page now redirects automatically to the main admin page on a successful login
• the button and logo for a payment method is displayed only if that method is enabled
• improved security
• improved code documentation
• consistently formatted code

Thanks again Geoff.