NanoMQ v0.4.1 Release Note

1. support LWT.
2. support Username/Password authentication
3. Improve CONNECT efficiency.
4. Fix concurrency bugs.

This is an emergency release to fix the conf priority issue. the params passed by Command-line gonna overwrite any other configuration from "nanomq.conf" If there is no conf information is provided, Nanomq will use default params to boot.