Add command for administrators to change channel publicity ingame rather than having to manually manipulate the database.

--HG--
branch : trunk

sql/updates/7430_world_command.sql

@@ -0,0 +1 @@
+INSERT INTO command VALUES ('channel set public', 3, 'Syntax: .channel set public  $channel $public\r\n\r\nChange password-changing ability for a channel. 1 for possible, 0 for GM only.');