TravisCI doesn't work with python3.5

[rethore]

TravisCI doesn't work with python3.5 distribution. This error has been reported in multiple places

$ pip install -U tox
You are using pip version 6.0.7, however version 7.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Collecting tox
  Downloading tox-2.3.1-py2.py3-none-any.whl (40kB)
    100% |################################| 40kB 7.3MB/s 
Collecting virtualenv>=1.11.2 (from tox)
  Downloading virtualenv-13.1.2-py2.py3-none-any.whl (1.7MB)
    100% |################################| 1.7MB 234kB/s 
Collecting py>=1.4.17 from https://pypi.python.org/packages/2.7/p/py/py-1.4.31-py2.py3-none-any.whl#md5=aa18874c9b4d1e5ab53e025008e43387 (from tox)
  Downloading py-1.4.31-py2.py3-none-any.whl (81kB)
    100% |################################| 86kB 1.4MB/s 
Collecting pluggy<0.4.0,>=0.3.0 (from tox)
  Downloading pluggy-0.3.1-py2.py3-none-any.whl
Installing collected packages: pluggy, py, virtualenv, tox
  Found existing installation: py 1.4.26
    Uninstalling py-1.4.26:
      Successfully uninstalled py-1.4.26
Successfully installed pluggy-0.3.1 py-1.4.31 tox-2.3.1 virtualenv-13.1.2
$ tox
GLOB sdist-make: /home/travis/build/rethore/FUSED-Wake/setup.py
py35 create: /home/travis/build/rethore/FUSED-Wake/.tox/py35
ERROR: InterpreterNotFound: python3.5
___________________________________ summary ____________________________________
ERROR:   py35: InterpreterNotFound: python3.5
The command "tox" exited with 1.
Done. Your build exited with 1.

[rethore]

This commit d5c2a1e attempted to reproduce a fix presented in travis-ci/travis-ci#4794