Henok alem py2 to py3

[henokalem]

All tests passing with 33% test coverage:

---------- coverage: platform darwin, python 3.6.5-final-0 -----------
Name                       Stmts   Miss  Cover
----------------------------------------------
socketio/__init__.py          19     14    26%
socketio/defaultjson.py       15      1    93%
socketio/handler.py          105    105     0%
socketio/mixins.py            30     30     0%
socketio/namespace.py        134     27    80%
socketio/packet.py           117      0   100%
socketio/policyserver.py      19     19     0%
socketio/sdjango.py           45     45     0%
socketio/server.py            90     90     0%
socketio/sgunicorn.py        109    109     0%
socketio/transports.py       180    180     0%
socketio/virtsocket.py       214    102    52%
----------------------------------------------
TOTAL                       1077    722    33%