0.4 - Performance improvements

The goal of this update is to make the game run at the 90fps target for setups with the specified minimum requirements. [h1]GPU Performance improvements[/h1] [list] [*]Lowered mesh and physics complexity [*]Switched to single pass stereo rendering [/list] [h1]World detail[/h1] [list] [*]Added new Building mesh types [*]Added Electrogun Turrets (WIP) [*]Improved helicopter model [/list] [h1]Gameplay[/h1] [list] [*]Helicopters now spawn dynamically [*]Added controller vibration feedback [*]Disabled vertical camera to reduce disorientation [*]Fixed an issue where hook physics behaved incorrectly after hooking onto a helicopter [/list]