Dist enhancements

Hi,

I've added a GitHub URL of this repository, so that MetaCPAN could render it on module page.

I also have added a Changes file following `CPAN::Changes::Spec`  format.

Following this format means that various tools can more easily process your distribution automatically.

You can find out more about this at Brian Cassidy's [CPAN::Changes Kwalitee Service](http://changes.cpanhq.org/), which is where I saw your module listed :-)

Cheers,
Sergey

PS: I'm doing this because I'm on a quest to help improve CPAN. Read more about the quest at [Questhub](http://questhub.io):

> http://questhub.io/realm/perl/quest/51f0337718ba7d3959000086

If you decide to update your other dists, feel free to log them in comments on the quest -- every dist helps!