Support abstraction for 'NOT IN' SQL structure

Support abstraction for 'NOT IN' SQL structure

Following a live discussion with Catrope.

When using Database::makeList() in LIST_AND or LIST_OR modes, you can now
suffix the field name with an exclamation mark.  It will negate the logical
boolean.

Example:
  $db->makeList( array( 'field!' => array( 1,2,3 ) );
  outputs:
    'field' NOT IN ('1', '2', '3' );

 $db->makeList( array( 'foo!' => array( 777 ) ) );
 outputs:
   'foo' =! 777

(note: tests not ran, please run them and ammend them)