Rename function viewHighScore to showHighScore for consistency.
Added GameOverScreen.
Added GameOverScreen to the main layout.
Lots of commits because I don't care.
Removed background.
Merge remote-tracking branch 'origin/game-over'

Conflicts:
	high_scores.txt
	src/procrastination/GamePanel.java
	src/procrastination/Procrastination.java
	src/procrastination/content/Level.java
	src/procrastination/content/Player.java