Add a README for the v2 unittests

v2/README-tests.md

+Ansible Test System
+===================
+
+Folders
+=======
+
+test
+----
+
+Unit tests that test small pieces of code not suited for the integration test
+layer, usually very API based, and should leverage mock interfaces rather than
+producing side effects.
+
+Playbook engine code is better suited for integration tests.
+
+Requirements: sudo pip install paramiko PyYAML jinja2 httplib2 passlib unittest2 mock
+
+integration
+-----------
+
+Integration test layer, constructed using playbooks.
+
+Some tests may require cloud credentials, others will not, and destructive
+tests are separated from non-destructive so a subset can be run on development
+machines.
+
+learn more
+----------
+
+hop into a subdirectory and see the associated README.md for more info.
+
+
+