This is the base code for the virt test compatibility
layer. We arrived at this initial version of the code
after significant work and previous reviews.

Basically the compatibility layer aims to let people
run virt-test tests inside avocado, giving them
avocado specific features, and letting them to get
used to the new avocado world.

Changes from v3 (v13):
* Fixed Ruda's comment about imp import;
* Made the entire test source/runner plugin code
  to fit into 80 columns.

Changes from v1 (v11):
* The LICENSE file was fixed to state that the files
  inside the plugin are GPLv2+ licensed (GPLv2 or later),
  per adereis's comments.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>