Bugfix and Enhancements

Fix the getting config REST API which throws exceptions.

Support to restart listeners when emqttd is running.

Specify a fixed tag for the dependency libraries.

emq-auth-jwt

Fix token verification with jwerl 1.0.0

emq-auth-mongo

Support $all variable in ACL query. (emq-auth-mongo#123)

Support both clientid and username variables in all queries. (emq-auth-mongo#123)