Lone Fury v002 Uploaded

Lone Fury v002 Changes

• Fixed: Asteroid spawning so the correct number are created per level.
• Added: Placeholder mines. They behave like asteroids at the moment, they need lethal explosions added.
• Added: Two Play.Date System Menu options for debugging:
 

• show fps [ ] toggles the usual Play.Date FPS counter, next to the score.
• show level [ ] toggles a different menu mode that shows the random level layout, as per this dev post.