Log Message:

Update to 0.48

  Build system has been changed from mk-files to mk-configure

  pkg_subgraph_deps:
    - manual page was added.
    - new option -t was added.
    - tsort(1)-like input is also accepted, i.e., two equal tokens on
      input mean isolated node of graph (package with no dependencies and
      dependent packafes)

  pkg_bin_summary:
    - manual page was added, usage message was also improved.