Dist enhancements

Hi,

I've made several minor fixes, so in order:

- added `utf8` pragma and UTF-8 Pod marker. This fixes [RT#87076](https://rt.cpan.org/Public/Bug/Display.html?id=87076)
- added GitHub repository address, so it could be nicely displayed at [MetaCPAN](https://metacpan.org/module/Acme::CPANAuthors::Portuguese)
- made some improvements in Changes file, so it would meet `CPAN::Changes::Spec`

You can learn more about the last change at [Brian Cassidy's CPAN::Changes Kwalitee Service page](http://changes.cpanhq.org/), and at corresponding quest at [Questhub](http://questhub.io/):

> http://questhub.io/realm/perl/quest/51f0337718ba7d3959000086