v03

• Added AI health pool
  • Once their health drops to zero, they are destroyed
• Added Player health pool
  • Once your health drops to zero, you are destroyed
• Added Damage to player laser
• Added Damage to enemy laser
• Projectiles that hit either player or enemy get removed on impact now (less clutter on the screen)
• Added the first version of scrolling background
  • I expect to adjust this down the road, e.g. change the scrolling speed depending on intensity of the level, more details (starfield, debris etc)