* Graceful Shutdown for windows and others
Restructures modules/graceful, adding shutdown for windows, removing and
replacing the old minwinsvc code.
Creates a new waitGroup - terminate which allows for goroutines to
finish up after the shutdown of the servers.
Shutdown and terminate hooks are added for goroutines.
* Remove unused functions - these can be added in a different PR
* Add startup timeout functionality
* Document STARTUP_TIMEOUT
David Svantesson