Unit tests and continuous integration

[femtotrader]

Hello,

I think it will be nice to add some tests (not with unittest package but using either nosetestsor py.test
Moreover continuous integration with Travis-CI will be a good idea
it will probably help to ensure Python 3 transition without regression on Python 2

Kind regards

[femtotrader]

Sorry I didn't noticed that there was doctest.

but PR is sent to add Travis-CI I think that all forks should have this so it will be easier to merge
(I think we should)

[femtotrader]

We just need a .travis.yml file like

language: python
python:
  - "2.7"
  - "3.3"

# command to install dependencies
install:
  - "pip install ."

# command to run tests
script: python tests/test_bunch.py

It will be nice if every active fork could enable this