level difficulty and highscore

• increase game speed
• increase difficulty per level (longer panic mode, shorter hunting mode, shorter bonus fruit time)
• highscore list with possibility to encrypt the list (see pacman --help)

SDL2

• changed to SDL2
• command line parameter (see pacman -h for help)
• level number
• show remaining bonus fruits

Game menu

• game menu with funny animations and with options menu and about info page
• toggle between window and fullscreen in options menu
• toggle between sound on and off
• q or escape to quit menu or game

Performance and sound

• more performance (means less CPU usage)
• sound
• close memory leak
• code review