Merge pull request #61 from ruda/test_runner

avocado.job: Create entry point for  plugable test runners.
Work in progress: Run tests on a libvirt domain.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
Add methods to send and receive files from VM.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
Pass the urls of the tests.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
avocado.plugins.vm: Add vm_test_runner.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
avocado.plugins.vm: Add vm_run_test()

Signed-off-by: Ruda Moura <rmoura@redhat.com>
avocado.plugins.vm: Using xchange plugin (work in progress).

Signed-off-by: Ruda Moura <rmoura@redhat.com>