Add tox.ini for tox (http://tox.testrun.org)
Add tox.ini for tox (http://tox.testrun.org)

tox: http://tox.testrun.org/

    $ pip install tox
    ...
    $ tox
    ...
      py26: commands succeeded
      py27: commands succeeded
      py33: commands succeeded
      py34: commands succeeded
      pypy: commands succeeded
      pypy3: commands succeeded
      congratulations :)

jaseg/python-prompt-toolkit,ALSchwalm/python-prompt-toolkit,niklasf/python-prompt-toolkit,ddalex/python-prompt-toolkit,melund/python-prompt-toolkit,jonathanslenders/python-prompt-toolkit,amjith/python-prompt-toolkit