Config class

Creating the pull request so that I can comment some lines ;)
Agreed, it can be done in a future PR.

For the `display_errors` value, we just need to do a private method in the class that will test all the cases. Something like:
```php
private function get_ini_display_errors()
{
    switch(strtolower(ini_get('display_errors')))
    {
    case 'on':
    case 'yes':
    case 'true':
    case '1':
        return TRUE;

    default:
        return FALSE;
    }
}
```