drupal 7.0-alpha6

Changes since DRUPAL-7-0-ALPHA5:

• Drupal has a new core theme: Bartik!
• Numerous fixes to the upgrade path, including basic tests. Getting very close! :)
• Numerous important security fixes.
• Numerous accessibility improvements.
• Setting up Private files is now optional, rather than required.
• Registry made more fool-proof and robust.
• Redesign of Field UI "Manage Display" screen, to reflect multiple view modes. Field UI screens are now also extensible from contrib.
• Re-implementation of Overlay without jQuery UI, to address numerous critical issues.
• User creation setting now defaults to "Visitors, with admin approval" for security.
• Installation will no longer fail when settings.php is not present. Nice usability improvement.
• Required modules are once again shown on the modules page.
• Many improvements to input formats and filters.
• Table prefixes are now per-database connection, rather than global.