[extras:lng:ja] use XCUBE_MAILERLOCAL_MAIL_LE in mailer

For issue xoopscube#104

XoopsMailerLocal use `XCUBE_MAILERLOCAL_MAIL_LE` if it defined.

If you would like to specify the line feed code of Subject passed to
mail() in a XoopsMailerLocal class, it is necessary to define constant
`XCUBE_MAILERLOCAL_MAIL_LE` .

The example of preload (XoopsMailerLocalSetLE.class.php)
```php
<?php
define('XCUBE_MAILERLOCAL_MAIL_LE', "\n");
```
Merge branch 'master' into 2.3