New version of Net::GitHub quiets LWP::UserAgent warning.

Unrecognized LWP::UserAgent options: autocheck stack_depth at /Users/schwern/perl5/perlbrew/perls/perl-5.18.1-thread/lib/site_perl/5.18.1/Net/GitHub/V3/Query.pm line 87.
Merge the features of Gitpan::Repo into Gitpan::Dist.

Gitpan::Repo turned out to be a largely redundant wrapper around Gitpan::Dist.
The original idea was to separate the concept of the distribution from how
it is stored.  So far it's easier to just treat it as one unit for
Gitpan's purpose.