New Python binding for TrbNet

New Python binding for TrbNet

The new Python binding for TrbNet is based on the code
originally submitted by Tobias Weber as "PyTRB.py".
The upgraded code is:

* a proper Python package called 'trbnet'
* divided into low- and high-level classes
  trbnet.core.lowlevel._TrbNet() and
  trbnet.core.highlevel.TrbNet()
* also uploaded to the Python Package Index PyPI
* in this commit in the version 1.0.2

The code was for some time developed on Github
in the repository https://github.com/pklaus/pytrbnet
and is now being synced to trbnettools under the
subfolder libtrbnet_python.