Changes:
* On stairs beside electicity line fixed transperent texture;
* Added light on stairs in small vent;
* Navigation mesh TSideUpper devided on two parts: TSideUpper and TCorridorUp;
* Bots now can use vent to reach bomb site;
* As players can't recognise where need to plant bomb, at bomb site added bomb site sign (same as many CS:GO maps);
* Added lights to "Back Door" entrance;
* Simplified wall above "Back Door" entrance;