AbsoluteUrls does not work when using VirtualDocumentRoot.

[jide]

$_SERVER['DOCUMENT_ROOT'] returns an erroneous value when used on a server configured with the apache VirtualDocumentRoot directive.

I modified the AbsoluteUrls extension to make it work using a famous trick which can be found on https://issues.apache.org/bugzilla/show_bug.cgi?id=26052.