* ansible-test - Clarify need for empty __init__.py
* ansible-test - Update code-smell boilerplate.
* Update code-smell boilerplate for core.
* Update future boilerplate test for ansible-test.
All ansible-test code (except for targets) and core-specific sanity tests now use the same boilerplate.
The test also checks for unwanted `__future__` and `metaclass` boilerplate.
* Relocate target tools to the correct directory.
Several tools used on target Python versions were incorrectly placed in the controller directory.
* Overhaul ansible-test integration tests.
* ansible-test - Fix import test pyyaml usage.
* ansible-test - Remove unused import.
* ansible-test - Fix traceback when pip is unavailable.
* ansible-test - Fix typo in port forwarding message.
* ansible-test - Fix controller logic in requirements install.
* Fix unit tests in ansible-test integration test.
Unit tests are now run for available Python versions which
provide `virtualenv` (Python 2.x) or `venv` (Python 3.x).
