Start on v2.0 - handle POD separate from Perl with new pmtools::new_pod_iterator()

1) Bumped version to v2.0, as the 'pmtools' module now contains
   new_pod_iterator() for iterating through the various names
   for a POD file (helps support separate POD from Perl files).
2) Fixed pman and podpath to use pmtools:new_pod_iterator() so
   separate POD from Perl is now handled.
3) pmfunc is now less broken, as it detects when the argument
   is not the name of a function in a module.