No obvious way to tell which release a site is running

Same as Issue #20439 except this is for release 4.6 (although the Issue tracker does not yet have a 4.6 in its version selection).

20439 says:

"There's no easy way for a site administrator to tell which version of Drupal software his site is running. This is particularly a problem when an administrator manages multiple sites at multiple hosts. The problem becomes even more exacerbated when the same admin only has limited time to update the software on sites, resulting in confusion as to just what version is running where.

While there are a lot of technical solutions to this problem, some of which I'd like to implement, this patch is the simplest and least invasive. It simply adds the CVS release tag name to each file which can take such a tag. An admin can thus look in any file and see which release it is."

This patch is for the DRUPAL-4-6 branch core files.

A similar one will be added to a separate issue for DRUPAL-4-6 branch contrib files.