Added gihub repo and made Changes conform to CPAN::Changes::Spec

Hi,

I've added the github repo details to Build.PL, so it will appear in the metadata. You'll need to delete META.yml before it regenerates with the repo in the metadata though.

I also dropped the leading 'v' off the versions in the Changes file. Your Changes file now conforms to CPAN::Changes::Spec. Following this format means that various tools can more easily process your distribution automatically.

Cheers,
Neil