empty value better see, ^Cigger is mouseover body (still better after ajax request), css fixes (chromium,FF,Opera,rekonq,IE), 1 sprite image in gray for icons

http://bugtracker.ispconfig.org/index.php?do=details&task_id=1681

I've NOT tested this fix, but i think it should be fine.
Someone with Dovecot, please test.

Fixed: PHP notice in tform_actions.inc.php