Add coveralls to testing

* Add .coveragerc
* Add coveralls badge
Merge pull request #176 from sharoonthomas/develop

Add coveralls to testing
Allow subdivisions to be fetched for all countries #4254

Review ID: 3283001
Merge pull request #177 from priyankarani/feature/test

Allow subdivisions to be fetched for all countries #4254
If email and password fields are blank , authenciate would return None