Lightning MCD and LOF Fix

Description

The Lightning has been buggy since day 1 and this patch attempts to change that. This fixes the "hole" in the LOF (Line Of Fire) templates for the center North wall segment in the Lightning. This also fixes all the "wall" objects in this ship so that your troops can't exit from the diagonals. Additional countermeasures had to be implemented to prevent the aliens from shooting/seeing in and X-COM units from shooting/seeing out. Specifically, it introduces "invisible" pillars (like in a UFO) to seal the joints in the diagonal walls and extends the LOF templates on the floor tiles to plug the gap between the floor and wall as well. Tests reveal that this ship is now a hermetically sealed coffin, like it was meant to be. ;)

Simply extract into your main game folder and if prompted to overwrite anything, answer "yes to all".

Edit 1st April 2012: Thanks to Conti-k for finally pointing out this has been broken all these years... Fixed at last!