Add orchestra.warden facade.

Signed-off-by: crynobone <crynobone@gmail.com>
Add orchestra/notifier facade.

Signed-off-by: crynobone <crynobone@gmail.com>
Refactor Orchestra\Support\Nesty::descendants()

Signed-off-by: crynobone <crynobone@gmail.com>
Merge branch '2.1'