This patch adds the very minimum infrastructure necessary for writing
and running functional/acceptance tests, including:

 * Documentation
 * The avocado_qemu.Test base test class
 * One example tests (version.py)

Additional functionality is expected to be added along the tests that
require them.
Signed-off-by: NCleber Rosa <crosa@redhat.com>
Message-Id: <20180530184156.15634-2-crosa@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
[ehabkost: fix typo on testing.rst]
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>