Fixing Versions for different configs

Just inserted back the old Generator logic for different versions and fixed the missing logic for different filters, depending on Model->alias i.e.

Configure::write('Media.filter.default.image', array(
    's' => array('convert' => 'image/jpeg', 'fit' => array(300, 300), 'compress' => 6)
));
Configure::write('Media.filter.ModelAlias.image', array(
    's' => array('convert' => 'image/jpeg', 'fit' => array(220, 220), 'compress' => 4)
));