XAO::Web sites can now be easily executed withing PSGI environment. For
example:

  XAO_SITE_NAME=example starman misc/xao.psgi
  XAO_SITE_NAME=example plackup misc/xao.psgi

Or:

  plackup -MPlack::App::XAO -e 'Plack::App::XAO->new(site => "example")->to_app'