7) 2017.9.9
7.1) feature: master can wait callback from children when reloading the specific children

6) 2017.9.5
6.1) feature: master can wait children to exit with sync or async
6.2) feature: master can kill SIGTERM children when reloading
6.3) bugfix: master_params.cpp 中的 init_conf_str_vars 函数在 master reload 时
有内存泄露

5) 2017.8.11
5.1) safety: master can't fatal for some configure error of any app service.

4) 2017.7.7
4.1) feature: master can stop or kill one service, stopping service is graceful
by closing the IPC pipe, and killing service is rude by signal SIGTEM children.
4.2) feature: add graceful stop API in master's web management interface.

3) 2017.6.26
3.1) protocol: changed the web management protocols.

2) 2017.6.25
2.1) feature: acl_master uses kernel event mode

1) 2017.6.18
1.1) feature: In Docker's running time, the master's pid was set to 1; When
stopping master by sending TERM singal to master's pid, master_sigdeath func
will be called and which'll send TERM to -pid that's the master's pid group,
but in docker the pid is 1, so we should stop the children in the other way.