Improved GPU performance and other fixes (Build 6)

[h2]Patch Notes - Build 6[/h2][p][/p][h3]Improvements:[/h3]

[p]Updated Unity version.[/p]
[p]Improved the nebula performance (GPU)[/p]
[p]Improved the aeroxite cloud performance (GPU)[/p]
[p]Added toggles in the graphic options to enable/disable the background image, stars, debris.[/p]
[p]\[Build 6.1] Added the classic movement scheme for gamepads.[/p]

[p][/p][h3]Bugs Fixed:[/h3]