uc_worldpay 6.x-1.0-rc1

Changes since DRUPAL-6--1-0-BETA1:

• re-commit to 6.x branch
• #369096 by alanburke, davej: Return a better completion page.
• #611440 by matason: Updated the test and live URLs, added the ability to change them through 'Worldpay settings'.
• #529760 by matason: Updated Worldpay logo to the latest RBS Worldpay logo.
• by matason: Tidy up, removed t() from 'title' key in hook_menu().
• #553796 by matason: Fixed the 'Back' button on the checkout review form
• by matason: Tidy up, coding standards, removed trailing spaces.
• #670682 by matason: Fixed payment parameters 'Enable test mode' and 'Test mode result' settings functionality.
• by matason: Added an option to have orders cancelled in Ubercart when the customer cancels during payment processing whilst on Worldpay servers.
• by matason: Fixed missing t().
• Updated text - 'Payments powered by RBS Worldpay', refactored generation of available payment types, removed inline CSS in favour of an external stylesheet.
• by matason: Improvements to settings form code, save only checked checkboxes, made Test and Live URLs required fields and added some validation.
• by matason: Removed uneccessary function_exists() checks, uc_order is a dependency, added uc_cart as a dependency.
• by matason: Replaced inline styles on review table with CSS in the external stylesheet.
• #790340 by matason, freatida: Fixed variable naming issue.
• by matason: Tidy up, added a @file comment to the install file.
• by matason: Tidy up, replaced instances of the text 'Worldpay' with 'RBS Worldpay'.
• by matason: Tidy up, added a comment about the ['array_filter'] hack and a @todo to keep an eye on the issue regarding fixing it.