Issue #1317628 by Albert Volkman, Gaelan, disasm, mjonesdinero, xjm: Clean up API docs for include files n-z

#874370 by Jeff Burnz, aspilicious, Cliff, mgifford, yoroy, et al: Fixed System messages need identifying icons (WCAG 2.0).

- Patch #812016 by effulgentsia, chx, redndahead, Damien Tournoud: themes cannot always participate in drupal_alter().

- Patch #807396 by Berdir, carlos8f, David_Rothstein: database errors not displaying during install.

- Patch #766100 by andypost: undefined function _system_rebuild_theme_data() when trying to run update.php.

#766100 by andypost: Fixed Undefined function _system_rebuild_theme_data() when trying to run update.php from D6 -> D7.

#679890 follow-up by Bojhan, aspilicious, and agentrickard: Remove more extraneous 'Please' in the interface.

#299308 by redndahead, Dave Reid, dropcube, catch, redndahead, and dbabbage: Add POD to installation requirements.

#592018 by mverbaar, Jacine, et al: Re-organize styles across stylesheets from system.module and separate presentational and behavior-supporting styles.

#547068 by sun, seutje, yoroy, Gábor Hojtsy, adrian, Bojhan, and markboulton: Use Seven theme for installation / updates.

#538660 by JacobSingh, dww, JoshuaRogers, adrian, Crell, chx, anarcat, and cwgordon7: Add a functioning Plugin Manager to core. Can you say module installation and updates through the UI? I knew you could! :D

- Patch #572618 by effulgentsia, pwolanin, sun: all theme functions should take a single argument. Code clean-up and performance improvement. Woot.

#321828 by Davy Van Den Bremt and Damien Tournoud: Move template_preprocess_maintenance_page() to theme.inc to allow Drupal to properly report fatal errors.

#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.

#531476 by aaron and mfb: Add favicon mimetype as a theme setting to avoid expensive calls to file system.