#242873 follow-up by pwolanin: Move new check_plain() check constants to bootstrap.inc so they're there in early bootstrap.

#142995 by dopry, drewish, quicksketch, jpetso, and flobruit: Adding hook_file_X(). This is an enabler of lots and lots of goodies. See CHANGELOG.txt for more. Awesome work, guys. :)

- Patch #232931 by mikey_p, flobruit et al: clarified the PHPdoc of drupal_add_feed() and drupal_add_link().

- Patch #308138 by mfer, Dave Reid: replace valid_email_address with filter_var and FILTER_VALIDATE_EMAIL.

#308399 by Damien Tournoud: Fix SimpleTest error handler to not spaz out and die when PHP errors are encountered.

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

- Patch #302763 by Dave Reid, Rob Loach: replace time() by ['REQUEST_TIME'] as per Rasmus' suggestion.  Removed drupal_referrer() for consistency.

- Patch #225450 by Crell, chx, bjaspan, catch, swentel, recidive et al: next generation database layer for Drupal 7.

- Patch #295564 by boombatower, Damien Tournoud: fixed drupal_http_request error and cleaned up some simpletest stuff.  We should have a much more funky 'all tests passed' screen.  Having all tests pass shouldn't be this boring.  Let's be a bit more creative and injest some fun ... ;-)

- Patch #268477 by MadHarold, Damien Tournoud, kkaefer, et al: untranslatable suffix in format_size()

- Patch #283806 by mustafau: fixed bug in drupal_http_request() and added some first drupal_http_request() tests to core.  Yay.

- Patch #287877 by dmitrig01: rename drupal_rebuild_code_registry() to registry_rebuild() for consistency.

- Patch #158992 by sun, quicksketch, zeta ζ, bangpound, Dries et al: inline Javascript could generate invalid XHTML.

- Patch #252013 by Eaton, pwolanin, Susurrus et al: drupal_render() now printes #markup, not #value.

- Patch #151902 by MadHarold et al: a better format_size() (and removed some excessive white space).