Lots of refinement still needed and runs only on POSIX systems. Windows will not get true graceful restarts (for now), but we will opt for very, very quick forceful restarts. Also, server configs are no longer put into a map; it is critical that they stay ordered so that they can be matched with their sockets in the child process after forking.

This implementation of graceful restarts is probably not perfect, but it is a good start. Lots of details to attend to now.