Update `conftest.py` to use the `pytest-flask` plugin
Add `pytest-flask` to test dependencies
Reverse the order of test requirements

Workaround for bug in setuptools. See https://bitbucket.org/pypa/setuptools/issue/196/tests_require-pytest-pytest-cov-breaks
for more details.
Update version number
Merge pull request #15 from vitalk/use-pytest-flask

Use `pytest-flask` package for testing