add mock to test requirements
add flask-testing to tests requirements
setup.cfg: copy nosetests configuration from .travis.yml

If one runs the unit tests via ``python setup.py nosetests`` then nose
complains about running thing within the testing directory. Copy the
nosetests configuration from .travis.yml to make running nose via
setup.py work.
.travis.yml: run nosetests via setup.py

Keep knowledge of how to run tests in one place, setup.cfg.
add stub API test case

Add a stub testing framework for the API. Currently there is one test
which makes sure that passing no parameters to the API results in a bad
request response.
tests: actually run a test for a simple API call

Make use of mock to mock out enough of the tawhiri data access API to
test the API request parsing logic. It might be less mucky to mock the
entire tawhiri.api.run_prediction function but that leaves very little
left which is actually tested.
Merge pull request #93 from rjw57/some-basic-tests

Get a very basic test of API working