4.0.0

• serve proc now accepts the amount of worker threads to use
• registerThreadInitializer is now a global proc (not tied to a GuildenServer)
• ctxWs web socket upgrade now accepts a callback closure (instead of initial message to send)
• can listen to multiple ports even with same handler (just register different handler callback proc for each port)
• new ctxBody handler for efficiently handling POST requests.
• new isRequest proc for efficiently inspecting request content
• new custom threadpool
• code fixes and cleanups