Added basic get/post unit tests
Added more unit tests

File post, API version selection, HTTP errors
Started photo API unit tests
Additional photo API unit tests
Add CLI testcases.
Add album unit tests
Check that local object's fields are empty after photo is deleted
Rename transform tests to be consistent
TestHttpErrors shouldn't inherit from TestHttp
Capture and check stdout/stderr during cli tests
Merge remote-tracking branch 'upstream/master' into unit_tests
Added tag unit tests
Reorganise tests into unit and functional categories.

Tox (and hence Travis) only runs unit tests
Functional tests can be run manually, with the default Python version
Updated test documentation
Update test readme file
Update functional test README file
Removed config secrets from travis setup, since we're now only running the unit tests
PyLint fixes
Ensure files are closed properly, to avoid Python3 warning
Ensure the test file is closed after use to prevent Python3 warnings