Update README to list all APIs (#1022)
Update README to list all APIs (#1022)

* Update README to list all APIs

* Update with samples

* Address PR comments

chingor13/google-cloud-php,googleapis/google-cloud-php,jdpedrie/google-cloud-php,googleapis/google-cloud-php,chingor13/google-cloud-php,googleapis/google-cloud-php,chingor13/google-cloud-php,jdpedrie/google-cloud-php,jdpedrie/google-cloud-php