Patch 0.9.4 - Unreal 4.18 upgrade, Vive support, and heavy optimization

Core

• Upgraded engine from UE 4.17 to 4.18
• Drastically reduced texture-memory usage by optimizing mip-maps
• HTC Vive should now work via the OSVR plugin (needs testing)
• Eliminated many unused materials and textures to lower required disk-space
• Joystick-input is now fed through the UE4 raw-input plugin
• Reduced all texture-pool sizes (varies with texture-quality setting)
• Lowered overall game-size by nearly 2GB (~50%)

Controls

• Angular drag is now customizable (very useful for joysticks and VR)
• Joystick-buttons are now customizable from any control-mapping field (shown as GenericUSBController Button)
• Up to 8 joystick-axes can now be mapped (must be manually set for now)
• Steam Controller plugin is now enabled

UI

• Improved visibility of menu-text
• Changed off-screen target-reticle to a simpler arrow-design
• Added angular-drag slider and joystick-axes fields to the controls-menu

Visuals

• Increased resolution of some skyboxes
• Reduced debris in frigate-explosions

Bugs

• Fixed issue with loading-screen hanging occassionally due to a race-condition
• Eliminated NULL-spawning attempts by injecting class-validity guards
• Removed excessive debug-logging from motion-controllers