Remove PHP 5.6 from allow failure.

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

Signed-off-by: crynobone <crynobone@gmail.com>
Merge branch '2.1' into 2.2

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

Conflicts:
	README.md