Dist enhancements

First I was going only to fix Changes file while doing [this quest](http://questhub.io/realm/perl/quest/51f0337718ba7d3959000086), but then I added a bit more:
* Added repository location to Makefile.PL, so it would be visible from [MetaCPAN](http://metacpan.org)
* Changed `use vars` declaration to `our`, since former marked obsolete in perldoc