Added bonuses and Breeders, bug fixes
-FEATURE: Added extra life-bonuses.
-FEATURE: Added invulnerability bonuses.
-FEATURE: Added Breeders.
-FEATURE: Added Eggs.
-FEATYRE: Added BabySnakes.
-CODE: Replaced the Sprite creation in all GameObjects' init-methods
with loadTexture(String).
-BUG: Restarting the game did set the spawn system to background mode.