* Add support log subsystem
* Replace logger calls to LOGi (LL_INFO)
* Add new global object: server_t g_srv
* Make current_header as static char array
* Make global struct g_cv which contain static Py strings
* Add new const values to global struct g_cv
* Add loglevel option to fastwsgi.py
* Fix bug then response body contain 0x00 symbol
* Add new header file: common.h
* Replace response buffer type to xbuf_t (new expanded buffer)
* Cleanup function build_response (remove waste alloc mem)
* Add extended logging into server.c
* Update submodule llhttp to 8.1.0 release
* Add functions build_response_ex and send_fatal
* Fix send error message then use Keep-Alive connection
* Fix call uv__socket_sockopt (first arg incorrect)