avocado.plugins.collector: Collect results in JSON format and archive logs.

Collect and output test results in JSON format,
implies option to archive logs in ZIP format.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
Merge pull request #68 from ruda/avocado_plugins_collector

avocado.plugins.collector: Collect results in JSON format and archive logs
avocado.utils.virt: classes for using VMs.

Signed-off-by: Ruda Moura <rmoura@redhat.com>
selftests/all/doc: Print full build output for better debug

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
.travis.yml: install python-libvirt

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Merge pull request #69 from avocado-framework/67-with-better-debug

67 with better debug