Engine: refactored setting data directory routine

This also fixes the case when command line argument, which defines data directory, does not have trailing slash
Common: fixed other cases of superfluous string growth

Signed-off-by: Ivan Mogilko <ikm_spb@yahoo.com>
Engine: fixed dialog options clickable area

Properly specify the interactable horizontal coordinates range for dialog options overlay.
Updated build version (3.3.0.1148)