- Patch #28482 by Uwe: add CVS $Id$ tags to all source files in Drupal core....

- Patch #28482 by Uwe: add CVS $Id$ tags to all source files in Drupal core. This allows admins to know exactly which version of which files they use. In addition I want to use CVS $Id$ tags in my upcoming security.module to check for possible vulnerabilities. That's not possible if some files simply don't have $Id$s.

Note: I also (mostly) unified the tags to use the "// ID" form instead of "/* ID */", but that's more of a cosmetic issue. I'm not sure whether *.txt files and the stuff in themes/ need tags(?).