Version 0.3. Big changes

- Implemented bullet functionallity to the character, but later moved to
the Game scene.
- Implemented bullet functionallity into the Game scene. Adjusted
maximum bullets to 30.
- Now the bullets are spawn in front of the ship.
- TODO: relative to bullets, make them spawn slower!
- Adjusted calculations for the player to stay in the window (don't go
out of bounds). Problems with the lower part of the screen.