Initial `basetests` app, still using `unittest`.
Add `unittest2` and `six` packages.
Merge branch 'develop' into feature/2417-add-a-base-test-suite-for-ka-lite

Conflicts:
	kalite/settings.py
Move `kalite.basetests` along with the other testing apps.
Initial management command and sqlite3 dependency test.
Merge branch 'develop' into feature/2417-add-a-base-test-suite-for-ka-lite
Merge branch 'develop' into feature/2417-add-a-base-test-suite-for-ka-lite
Upgrade `unittest2` to use 0.7.1.
Refactor of `dependencies.py` to use custom logger so we can display a message and the result at the same line.
Create a `DependenciesTest` class from which the tests will inherit.
Fix to use `sqlite_version_info` to get the correct sqlite3 version.
Remove unneeded test case and refactor calls to `self._fail()` method.
Some refactors for the custom logging and added more constants.
Test read-only access to content path.
Add more initial unit tests.
Merge branch 'develop' into feature/2417-add-a-base-test-suite-for-ka-lite
Remove the delays for unit tests.
Add tests to check installed apps and test for initial python packages.
Complete the list of python-packages required and also does check of their version.
Merge branch 'develop' into feature/2417-add-a-base-test-suite-for-ka-lite
Test access to and format of json files at `/data/khan/` folder.
Check if django can serve on production port.
Minor refactor of `student_testing.tests` to pass unit tests.