eg/plpinfo.plp demo/status page

Demo page reporting about the current status of Perl and PLP. Useful as
test page (see if correct versions are loaded as they should, and what
variables are set), or at least as a somewhat larger example of a plp
page.

Modelled closely after PHP's phpinfo() output (even color scheme is the
same, albeit html is much cleaner) to keep it as familiar as possible to
php switcheroos.