Merged

r30030 | srichter | 2005-04-18 16:31:36 -0400 (Mon, 18 Apr 2005) | 8 lines

Moved zope.server.http.http_date to zope.app.http.httpdate, since it
contains some utilities that are useful beyond the server, which will be
removed shortly.

Also, zope.app.session used this module, which made it dependent on
zope.server, sigh.