Update to 0.60.0
  pkg_update_src_summary:
    - Fix for the case when there are no updated/new packages, but
      removals exist.
    - Resulting summaeries are postprocessed by pkg_summary2bb_pkgs.
    - Option -v was added

  pkg_subgraph_deps:
    - Fix for option -1

  pkg_digger:
    - Minor fix. -sf outputs both fields and strategies.
    - All pkg_digger(1) backends return plain summaries on -1|-3|-9.
      Option -r was removed from pkg_digger_{summary,installed}

  pkg_digger_summary:
    - Implementation for option -n.

  pkg_summary2bb_pkgs:
    - Additional error checks.

  Man pages for pkg_digger, pkg_digger_summary, pkg_digger_installed
  were updated.

(cheusov)