added IO'18 pong talk an code in featured section
added IO'18 pong talk an code in featured section

Change-Id: I30c84cef6200fb0cf102456a3143d2ac3087d8be

GoogleCloudPlatform/tensorflow-without-a-phd,GoogleCloudPlatform/tensorflow-without-a-phd,GoogleCloudPlatform/tensorflow-without-a-phd,GoogleCloudPlatform/tensorflow-without-a-phd