Add more interface :
  EventLoop* getNextLoop(uint64_t hashCode);
  bool started() const

On some occasions, we need to process some tasks with the some type
always in the same working thread.
Add comments for Inspector:add. and fix one spelling mistarsk
Expose some detail implement : sockets::sockaddr_cast.
And add more interface : sockaddr_in_cast
And add bool setNonblocking(int sockfd);