Corrections and Post Credit Scene

This update corrects bugs, lays groundwork for more hand positions, and adds a post credit scene.

Bug Fixes:

• Fixed bug where "Reds" spawning was not curtailed when portal "becomes" in-active.
• "Double" vision due to fog fixed in TC cut scene.

Updates:

• Removed Vive controller diagram in help.
• Added detail to Tau Ceti system poster.
• Hints button disabled on controller menu for hard level.
• Refactored hand model code, added minor second grip position for hand.
• Improved backpack attach and detach to avoid minor glitches.
• Added post credit scene.