#497118 by chx, catch, pwolanin, JoshuaRogers, and Jacob Singh: Remove the function registry. While the hope was that this would result in improved performance for low-end hosts, it comes at the expense of critical development experience problems and less benefit than something like APC. Class registry remains intact to facilitate autoloading.

Of all the patches to accidentally commit without a message. :( Rolling back registry rip. Let's try that again.

#326539 by JohnAlbin, sun, cha0s, ultimateboy, Rob Loach, Damien Tournoud: Convert 'class' attribute to use an array, not a string.

#509398 by adrian: Turned install profiles into modules with full access to the Drupal API. Almost all WTFs/minute now removed from install profiles. Woohoo! :D

#517814 by jmstacey, justinrandell, pwolanin, drewish, Jody Lynn, aaron, dopry, and c960657: Converted File API to stream wrappers, for enhanced private/public file handling, and the ability to reference other storage mechanisms such as s3:// and flicker://.

- Patch #545356 by Damien Tournoud: sidebars were broken in install.php, update.php, and the expert profile due to a previous patch that made the sidebar regions more semantic for RTL support.

- Patch #199774 by dww, ugerhard, brianV, John Morahan: make it more 'natural' to enable security notification e-mails.

- Patch #524728 by David_Rothstein, JoshuaRogers, JacobSingh et al: refactor install.php to allow Drupal to be installed from the command line.

- Patch #482646 by Dave Reid et al: check for existence of ['HTTP_USER_AGENT'] for the SimpleTest user agent.

- Patch #497612 by Moshe Weitzman et al: harden user login by correctly using the form API.  Complete commit now.  Thank you, thank you.

- Patch #202775 by michaelfavia, jabapyth: fixed database testing and error handling during installation.

- Patch #474156 by brainless: fixed database prefix validation.  We need tests for the installer. ;-)

- Patch #428744 by Gabor: make the main page content a real block and clean up some of the content API.

- Patch #392362 by Xano, Dave Reid: remove clean URL option from the installation process -- automatically enable clean URLs when possible, or hide the option when clean URLs cannot be enabled.

- Patch #254491 by chx, catch, justinrandell, pwolanin, David_Rothstein, et al: centralized static caching to improve testability of the Drupal code, and to remove $reset-parameters.  Thanks for taking the time to convince me, catch!