STELLAR NOVA graphics and gameplay improvement

Enemies and obstacles now have sprites that replace cubes and circles..

4 bonuses are in place: 

-one which doubles the points gained

- one which temporarily stops projectiles

- one which allows projectiles to be attracted within a defined radius

-and the fourth which causes a projectile to appear which travels the map and destroys enemies or the troublemakers

a scale is set up depending on the effectiveness of the projectiles in increasing the main bar