Log Message:
filesystems/tahoe-lafs: Update to 1.16.0

Packaging changes:

  Mark as incompatible with python 2.7, compared to previous release
  which is 2.7 only.

  Rototill dependencies to align with setup.py, dropping several
  previous ones.

Upstream news:

  1.16.0:

    The major change in this release is the completion of the Python 3
    port -- while maintaining support for Python 2. A future release
    will remove Python 2 support.

    The previously deprecated subcommands "start", "stop", \ 
"restart"
    and "daemonize" have been removed. You must now use "tahoe \ 
run"
    (possibly along with your favourite daemonization software).

    Several features are now removed: the Account Server,
    stats-gatherer and FTP support.

  Previous to 1.16, but new to pkgsrc in this update:

    Magic Folder has been removed to a separate project.

    New command 'tahoe status'.