Add a high scores table
Better shield handling

Add a damage rate limiter, which makes you invincible for a short time after
you get hit. This prevents you getting damaged twice by the same enemy.

Make the shield blink when you get hit, as an extra visual indication that
you've been hit. When the shield level drops to zero, the shield vanishes from
around you.
Adding the Nuke script I created the models in.
Update the TODO
Update the gitignore to skip the ScreenShots dir
Ability to quit & take screenshots from the standalone version