Add more docs to cover corner cases and different versions of Kafka

* In some 0.8.x versions of Kafka, there is kafka_create_topic.sh but in other versions, there is kafka-topics.sh script. Covering both cases.
* Starting zookeeper-server on port 2181 (default in config/zookeeper.properties) throws Exception on some machines but doesn't on others. Document that scenario. 
true. I have added the script for other versions just below (bin/kafka-topics.sh). 
I am not sure if we want to restrict people to download only 0.8.0 since its not a limitation on the app but with the scripts change in kafka.