Convert to mysqli

This commit converts all mysql_* function to the appropriate counterparts
in mysqli.
I used this tool for most of it:
https://github.com/philip/MySQLConverterTool
This makes it possible to continue using MysqlDumper with PHP 7.0

config_overview.php

@@ -355,7 +355,7 @@ if (isset($_POST['save']))
 		{
 			if (MSD_mysql_connect())
 			{
-				$res=@mysql_selectdb($to_add,$config['dbconnection']);
+				$res=@((bool)mysqli_query($config['dbconnection'], "USE " . $to_add));
 				if (!$res === false)
 				{
 					$databases['Name'][] = $to_add;