rework the NameVirtualHost documentation to hopefully be a little

less confusing and match the conventional wisdom of the various
support fora.

Provide a longer example that demonstrates the 1:n nature,
relation to IP-based vhosts, and always uses a port.

Avoid phrasing that makes NVH look like Listen.

Remove the over-complicated hints about NVH impact on _default_ and base
server configs, which boils down to the basic ip-based vhost mapping
algorithm.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@766945 13f79535-47bb-0310-9956-ffa450edef68