Add propper client initialization

-add client states to avoid server sending data to uninitialized clients
  -don't show uninitialized clients to other players
  -propper client disconnect handling
Minor comment fixes in server
Minor bugfixes in connection
  -improved peer id calculation
  -honor NDEBUG flag
  -improved disconnect handling
  -increased initial send window
Remove some dead code

src/CMakeLists.txt

@@ -308,6 +308,7 @@ set(common_SRCS
 	connection.cpp
 	environment.cpp
 	server.cpp
+	clientiface.cpp
 	socket.cpp
 	mapblock.cpp
 	mapsector.cpp