Powerups and a base for other features

- The second powerup is now implemented! This is the candy cane shell that automatically finds the nearest cone obstacle (even if it is behind you) and moves to destroy it.

- A third powerup is now here! This is a 3 second powerup that doubles your speed.

- Both shell powerups now delete after 5 seconds to not cause any lag.

- In the level select screen it says "You have not completed this difficulty yet" over each difficulty. This is the base for a future implement of a save system that tells you which difficulties you have already completed and which you have not. This may be in the form of a star or a box that lights up when you have completed it.

- The camera that follows the player has a better angle allowing you to see better where the shells you shoot head to.

-A color changing border and animated name is now added in the menu screens.