net-p2p/py-tremc: create port

Curses interface for transmission.

Python3 fork of the no longer maintained transmission-remote-cli. Some
extra modifications have been included and development will follow the
original project as much as possible.

WWW: https://github.com/louipc/tremc

Submitted by: lbdm@privacychain.ch
Differential Revision: https://reviews.freebsd.org/D13618