Closes #20

Added support for tox. Installing tox (via pip install tox) and then running the command `tox` at the top level will create a separate venv and search through the entire nidaba project for py.test tests to run.
Update README.md
Added __version__ to /nidaba/__init__.py
Added Chillar's PR
Fixed tox integration
splitted requitement files
added .travis.yml