add repository URL and homepage to meta files
brush up Pod
reduce warnings on recent perls

`experimental` pragma disable warnings which are now being emitted
by default for some of the features (e.g. `given`..`when` syntax)
Merge branch 'dist-enhancements' of github.com:sergeyromanov/libwww-hkp-perl into sergeyromanov-dist-enhancements
fix typo