Bugfix that Auth::is() actually handles array, as illustrated in the doc.

Signed-off-by: crynobone <crynobone@gmail.com>
Improve code organization and docblock.

Signed-off-by: crynobone <crynobone@gmail.com>
Rename Orchestra\Auth\Acl\Environment::shutdown() to finish().

Signed-off-by: crynobone <crynobone@gmail.com>