Update Demo - 1.1.0

Changes:

* Project updated to the latest engine version — 4.4.1.

* Added stamina indicator.

* Grenade explosion wave now affects crates.

* Increased flashlight brightness.

* Fixed walking and running animations for the player.

* Added recoil for SMG and AR2.

* Fixed a bug where AI wouldn't turn towards the player when shot from behind.

* Fixed the issue with the "sliding" pyramid of zombies and headcrabs.

* Grenade explosion time reduced from 4 seconds to 3.

* AI has been updated and optimized.

* Fixed AI getting stuck at corners.