[Bug Fix] Fix #guild rename, #killallnpcs, and #worldwide message errors. (#1904)

- #guild rename was checking argument count and not allowing you to rename guilds to names that had spaces.
- #killallnpcs was crashing zones when used sometimes due to getting a nullptr somewhere in the loop.
- #worldwide message was using just the first word of the message sent using the command, not all of them.

zone/gm_commands/guild.cpp

@@ -225,10 +225,7 @@ void command_guild(Client *c, const Seperator *sep)
 
 		guild_mgr.ListGuilds(c);
 	} else if (is_rename) {
-		if (
-			arguments != 3 ||
-			!sep->IsNumber(2)
-		) {
+		if (!sep->IsNumber(2)) {
 			c->Message(Chat::White, "Usage: #guild rename [Guild ID] [New Guild Name]");
 		} else {
 			auto guild_id = std::stoul(sep->arg[2]);