STY: PEP8 on Python files
TST: use assert_allclose in unit tests
TST: fixed all doctests.

Examples in function documentation can now be checked using nose using:
nosetests --with-doctest
TST: .travis.yml file for CI testing
Merge pull request #11 from jjhelmus/master

TST: Fixed up unit and doc tests, set up continue integration testing on Travis CI.  calctw unit test result corrected.