BrowserGit: Use git-rev-list to get a list of commits

sub get_commits {

    my ($commit, $commit_stop) = @_;

    my @res = ($commit);

    return @res if $commit eq $commit_stop;

    my ($parents) = git_cmd_ch('git', 'show', '-s', '--format=%P', $commit);

    foreach my $p (split(' ', $parents)) {

        push @res, get_commits($p, $commit_stop);

    }

    return @res;

    my ($out) = git_cmd_ch('git', 'rev-list', '--topo-order',

                           "$commit_stop^..$commit");

    return split "\n", $out;

}

sub get_commits_by_branch {