Multiple permissions checked in Server::getInstance()

This is done like the one in `Command::testPermissionSilent()`, where permissions are connected via semicolons (`;`) and they are checked with `OR`, where the player must have at least one permission to read.

src/pocketmine/Server.php

@@ -1476,20 +1476,23 @@ class Server{
 
 	/**
 	 * @param string $message
-	 * @param string $permission
+	 * @param string $permissions
 	 *
 	 * @return int
 	 */
-	public function broadcast($message, $permission){
-		$count = 0;
+	public function broadcast($message, $permissions){
+		$recipients = [];
+		foreach(explode(";", $permissions) as $permission){
 			foreach($this->pluginManager->getPermissionSubscriptions($permission) as $permissible){
 				if($permissible instanceof CommandSender and $permissible->hasPermission($permission)){
-				$permissible->sendMessage($message);
-				++$count;
+					$recipients[spl_object_hash($permissible)] = $permissible; // do not send messages directly, or some might be repeated
 				}
 			}
-
-		return $count;
+		}
+		foreach($recipients as $recipient){
+			$recipient->sendMessage($message);
+		}
+		return count($recipients);
   	}
 
 	/**