Count packages, subs, lines, etc. of many files.

Changes for v1.0.2

• Fix https://github.com/matisse/Perl-Metrics-Simple/issues/12
• Change `_rewrite_moose_method_modifiers` in `Perl/Metrics/Simple/Analysis/File.pm` to check if a node supports the `literal` method and use `string` instead if it does not. Changes based on contribution by https://github.com/jwrightecs
• Fix typos in File.pm (thank you Florian Schlichting, fschlich)