Revert "Issue #22336 by quicksketch, rfay, scor, Rob Loach, boombatower, tstoeckler, kbahey: Move all core Drupal files under a /core folder to improve usability and upgrades."

This reverts commit f0a16bf2.

Issue #22336 by quicksketch, rfay, scor, Rob Loach, boombatower, tstoeckler, kbahey: Move all core Drupal files under a /core folder to improve usability and upgrades.

- Patch #76824 by geerlingguy, xjm, droplet, kbahey: Drupal should not handle 404 for certain files. Oh yeah.

- Patch #156582 by c960657, pwolanin, townxelliot, Damien Tournoud, kbahey, mikeytown2, drico, jpmckinney: drupal_http_request() should support timeout setting.

- Patch #778950 by aspilicious, jhodgdon, kbahey: fixed politically charged example in system.api.php.

- Patch #319406 by AlexisWilke, Dave Reid, Damien Tournoud, kbahey:  should only be cleared in the parent watchdog() call.

- Patch #208793 by kbahey, Damien Tournoud: stop hardcoding the HTTP protocol version where possible.

- Patch #235821 by kbahey and pwolanin: include upgrade path for cron changes, improved security of key.

#175117 by kbahey: developer improvement: include caller function name and user name in SQL queries for the query log when debug mode is turned on, so debugging gets easier

#146386 by kbahey: refactor 'submitted by user - date' themeing and make it more verbose to translate

- Patch #67893 by kbahey, dww, alienbrain, asimmonds et al: made it possible to filter log messages in the database log.

- Patch #63881 by kbahey and jakeg: improved Drupal's logging functionality.  Added support for external loggers, and included a small syslog module into core.

  (Untested because the admin/settings page doesn't work yet.)

- Patch #16829 by kbahey: separated the forum block for sake of consistency with other blocks.