Issue #1887: Equipped items do not emit sounds

Added playing of sounds for equipped items (at this moment only for lights).

Signed-off-by: Lukasz Gromanowski <lgromanowski@gmail.com>
This looks strange. When group is < 0 it means we are inserting a body part, not an equipment part, so the code for sounds should be skipped entirely instead of using Slot_Helmet.