Add integration testing

[tspenov]

Check whether all queries to sanbase return result

[IvanIvanoff]

Should these tests always run in the CI as they require internet and sanbase?

[tspenov]

@IvanIvanoff There is some tradeoff with running tests that require external dependancy but I think having this kind of integration test will be more beneficial than making problems. We can try it on and see how it goes.

[valo]

Can we run these tests with a special command and not run them by default when building the PRs? This way we will be able to define a separate build job which runs these once a day?

My concern is that if sanbase goes down all the builds will stop working and the master branch will be blocked...

[tspenov]

The command for running integration tests is:

python setup.py nosetests -a integration