Meta commands
-------------
-PLUGIN [string]
-Run plugin code in ./plugins/[argument], with argument only consisting of
-alphanumeric characters and underscores.
-
PING
Write "PONG" line to ./server_run/out file.
God commands
------------
+PLUGIN [string]
+Run plugin code in ./plugins/[argument], with argument only consisting of
+alphanumeric characters and underscores.
+
TURN [0 to 65535]
Set world turn to argument. (Initial value: 0.)