Perl extension for converting Pod to old-style Pod

 Pod::Plainer uses Pod::Parser which takes Pod with the (new) 'C<< .. >>'
 constructs and returns the old(er) style with just 'C<>'; '<' and '>' are
 replaced by 'E<lt>' and 'E<gt>'.
 .
 This can be used to pre-process Pod before using tools which do not recognise
 the new style Pods.