- Improve collisions. Now up to 3 pipes are check to avoid collision
  undetection for far  players
- Improve score system. Score is incremented only for new pipes
- Each pipe has an ID (see previous point)
- Fix bug in server part. If someone join the game, he can't change it's
  status if a game is running
- Avoid ghost effect on client side by not drawing a new player during a
  game
- Add new feature: you can now see high scores at the end of each game
- Update scoreSystem.js to retreive high scores
- Add new panel on client to display high scores
- Add favicon
- Fix typo bug on Unix system thanks to aberaza ;)