Handle error when message is undefined

Fix #12

Fix unhandled promise rejection hang

Fix #11

Use async commit rather than sync commit

BUG FIXES

Changes the commit mode to async to fix an issue of consumer trying to commit while consumer group is rebalancing. #6

Update to node-rdkafka 2.7.4

This release is using a newer version of node-rdkafka to correct the size of the module. Previously the node-rdkafka was built with unnecessary files result to over 900MB in size. The original issue was Blizzard/node-rdkafka#670

First Release

v0.0.1

Fisrt Release