Python3Upgrade

[YufengXin]

There are a number of things that need to be taken care of. (1) using the Futurize tool solved most of the syntax upgrade (print...); (2) byte and str compatibility, esp. in socket communication; (3) upgrade to python3, pip3, and future in the vagrant file (4) change in the Dockerfile (5) "relative import" doesn't work well, back to the "absolute import". (6) invoking "Ryu-manager" in the RyuControllerInterface.

### Automatic conversion to Py2/3
Futurize stage 1

futurize --stage1 -w /**/.py >future-step1-port.txt
Python2.7 unittest seem fine
conda activate python27
export PYTHONPATH=/Users/yxin/NSF/AW-SDX-Audit-Local/atlanticwave-proto
pip install --requirement requirements.txt
python -m unittest discover -v
conda deactivate

Python3 unittest causes multiple failures in dependencies so continue:

• Futurize stage 2
  . futurize --stage2 /**/.py
• Go through all the python modules to change:
  .metaclass
  .pickle (loads byte, no str; dump str to bytes)
  . list(dict.keys())
  . Modifying socket implementation due to the incompatibility between str and bytes.
  -update requirements.txt: ryu4.34, Flask
• Making changes in vagrant, Docker-file, run_sdx.sh, run_lc.sh, and vendor-updates:
  . use python3 as the default python
  . use pip3
  . use Ubuntu 18.04 in docker and ryu4.34

Going through all the unittest.

./lib
./shared
./localctlr
./sdxctlr

Jenkins deployment in vagrant