Description:
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When I invoke phd with general package
$ phd -d ~/phpdocs/doc-base/.manual.xml -p book.rrd -o /var/www/phprrd/
-f xhtml

No manual pages for classes are rendered, it's correct, because General package doesn't support 'phpdoc:classref'. 

Problem is that in final xhtml output are links (<a href>) for these non existed pages. I thinks it's bug, because it confuses end user.

Maybe consider printing warning message if some features isn't supported in some package.

When PHP package is used (--package PHP) everything is good.