Various configuration / build / test improvements

- Set minimum Perl and EU::MM versions and overhaul Makefile.PL
- Remove the generated META.yml file from source control
- Add .gitignore and MANIFEST.SKIP files
- Update copyright
- Add optional POD testing (skipped unless AUTHOR_TESTING)
- Make code Perl::Critic clean
- Add optional Perl::Critic testing (skipped unless AUTHOR_TESTING)
- Add optional POD coverage testing (skipped unless AUTHOR_TESTING)
- Reformat Changes file as per CPAN::Changes::Spec
- Add optional Changes testing (skipped unless AUTHOR_TESTING)