This commit consists of:
1) Change kafka/zookeeper ports mapping to allow for scaling via
   docker-compose
2) Use the afkak consumer example when subscribing to kafka messages
3) Remove dependency on kafka-python
4) Update the Build.md file with instructions on how to listen to kafka
   messages
diff --git a/compose/docker-compose-system-test.yml b/compose/docker-compose-system-test.yml
index 4fec883..aadeebc 100644
--- a/compose/docker-compose-system-test.yml
+++ b/compose/docker-compose-system-test.yml
@@ -6,7 +6,7 @@
   zookeeper:
     image: wurstmeister/zookeeper
     ports:
-      - "2181:2181"
+    - 2181
     environment:
       SERVICE_2181_NAME: "zookeeper"
   #
@@ -15,7 +15,7 @@
   kafka:
     build: ../kafka
     ports:
-      - "9092:9092"
+     - 9092
     environment:
       KAFKA_ADVERTISED_HOST_NAME: ${DOCKER_HOST_IP}
       KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181