Adding new util function for topics validations (#495)
Adding new util function for topics validations (#495)

* Adding new function for topics validations

Leaving the `validateTopics` topics function as it is because I believe it is meant for validating the topics coming from the `send()` function. Not sure, though.

`validateCreateTopics` contains following checks which are similar to what is been done for Kafka here [https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/common/Topic.scala]

- check if the topic is empty.
- check if the topic is . or ..
- check if the topic length is greater than 249 characters.
- check if the topic, is not ASCII alphanumeric.

* Update utils.js

For build fix.

* Update utils.js

Fixes as per suggestion.

SOHU-Co/kafka-node,SOHU-Co/kafka-node,SOHU-Co/kafka-node