Added link to github ToS and updated github repo link in metadata

Hi,

I saw a pointer to this on [Questhub](http://questhub.io/realm/perl/quest/51f0d25318ba7dcf4b000037) and reading the doc, saw the point about github terms of service and then wanted to read them. So have added a link.

Also noticed that the github repo wasn't showing up in the sidebar on MetaCPAN, as Makefile.PL doesn't have the new way to specify the repo.

Neil