Switch from Doctest to Nosetests

Address #51

Switch tests from Doctest to Nosetest as Nosetests is a less busy
testing environment. Tests were moved within `pymks` so they can be
installed with the main package. Also removed FiPy test dependency as
this introduced a completely pointless dependency.
Run all tests when installed

Address #51

Changed name from test to _test to avoid Nosetests recursive failure.
Rename `_test` to `test`

Address #51

Rename `_test` to `test` by using the `@nottest` decorator in
Nosetest. The `test` function was originally changed because it was
recursively being added to the tests leading to a recursion error.