Improved handling of IP address as a virtualhost address and

introduced "_default_" as a synonym for the default vhost config.

Submitted by: Dean Gaudet, PR #212
Reviewed by: Roy Fielding, Chuck Murcko


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@77720 13f79535-47bb-0310-9956-ffa450edef68